Abstract IA-018: Molecular landmarks of tumor hypoxia across cancer types

Many primary tumor sub-regions have low levels of molecular oxygen, termed hypoxia. Hypoxic tumors are at elevated risk for local failure and distant metastasis, but the molecular hallmarks of tumor hypoxia remain poorly defined. To fill this gap, we quantified hypoxia in 8,006 tumors across 19 tumor types. In ten tumor types, hypoxia was associated with elevated genomic instability. In all 19 tumor types, hypoxic tumors exhibited characteristic driver mutation signatures. We observed widespread hypoxia-associated dysregulation of miRNAs across cancers and functionally validated miR-133a-3p as a hypoxia-modulated miRNA. In localized prostate cancer, hypoxia was associated with elevated rates of chromothripsis, allelic loss of PTEN and shorter telomeres. These associations are particularly enriched in polyclonal tumors, representing a constellation of features resembling tumor nimbosus – an aggressive cellular phenotype. Overall, this work establishes that tumor hypoxia may drive aggressive molecular features across cancers and shape the clinical trajectory of individual tumors.

Citation Format: Vinayak Bhandari, Christianne Hoey, Lydia Liu, Emilie Lalonde, Jessica Ray, Julie Livingstone, Robert Lesurf, Yu-Jia Shiah, Tina Vujcic, Xiaoyong Huang, Shadrielle M.G. Espiritu, Lawrence E. Heisler, Fouad Yousif, Vincent Huang, Takafumi N. Yamaguchi, Cindy Q. Yao, Veronica Y. Sabelnykova, Michael Fraser, Melvin L.K. Chua, Theodorus van der Kwast, Stanley K. Liu, Paul C. Boutros, Robert G. Bristow. Molecular landmarks of tumor hypoxia across cancer types [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr IA-018.

Anakinra in hospitalized patients with severe COVID-19 pneumonia requiring oxygen therapy: Results of a prospective, open-label, interventional study

Objective

The aim of this study was to evaluate the efficacy of anakinra in patients who were admitted to hospital for severe COVID-19 pneumonia requiring oxygen therapy.

Methods

A prospective, open-label, interventional study in adults hospitalized with severe COVID-19 pneumonia was conducted. Patients in the interventional arm received subcutaneous anakinra (100 mg twice daily for 3 days, followed by 100 mg daily for 7 days) in addition to standard treatment. Main outcomes were the need for mechanical ventilation and in-hospital death. Secondary outcomes included successful weaning from supplemental oxygen and change in inflammatory biomarkers. Outcomes were compared with those of historical controls who had received standard treatment and supportive care.

Results

A total of 69 patients were included: 45 treated with anakinra and 24 historical controls. A need for mechanical ventilation occurred in 14 (31%) of the anakinra-treated group and 18 (75%) of the historical cohort (p < 0.001). In-hospital death occurred in 13 (29%) of the anakinra-treated group and 11 (46%) of the historical cohort (p = 0.082). Successful weaning from supplemental oxygen to ambient air was attained in 25 (63%) of the anakinra-treated group compared with 6 (27%) of the historical cohort (p = 0.008). Patients who received anakinra showed a significant reduction in inflammatory biomarkers.

Conclusion

In patients with severe COVID-19 pneumonia and high oxygen requirement, anakinra could represent an effective treatment option and may confer clinical benefit.

Trial registration number

ISRCTN74727214.

Sex differences in oncogenic mutational processes

Sex differences have been observed in multiple facets of cancer epidemiology, treatment and biology, and in most cancers outside the sex organs. Efforts to link these clinical differences to specific molecular features have focused on somatic mutations within the coding regions of the genome. Here we report a pan-cancer analysis of sex differences in whole genomes of 1983 tumours of 28 subtypes as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We both confirm the results of exome studies, and also uncover previously undescribed sex differences. These include sex-biases in coding and non-coding cancer drivers, mutation prevalence and strikingly, in mutational signatures related to underlying mutational processes. These results underline the pervasiveness of molecular sex differences and strengthen the call for increased consideration of sex in molecular cancer research.

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 scale1-3. 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 promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10-18.

Abstract 3771: Oncogenes and tumour-suppressors drive differential retinoblastoma evolution

Unlike any other tumour type, retinoblastomas can be driven by only two tumour-initiating events: bi-allelic loss of the tumour suppressor RB1 or amplification of the MYCN oncogene. These mutations drive morphologically indistinguishable tumours that arise at different ages, providing a unique model system to evaluate the influence of initiating mutation on tumour evolution. We performed high-resolution copy number analysis of 101 retinoblastoma and whole genome sequencing of 23. These data reveal that different initiating mutations cause probabilistic changes in somatic point and copy number mutations, but large changes in genomic rearrangements and mitochondrial number. Independent of the initiating mutation, retinoblastomas harbour multiple subclonal populations that preferentially accrue point mutations after subclonal diversification. These subclonal structures suggest caution when choosing chemotherapeutic strategies for primary treatment. Overall, initiating mutations influence evolutionary trajectory more than specific driver mutations: RB1- and MYCN-driven tumours harbour distinct mutational processes, sequences of mutation acquisition and patterns of subclonal diversification. These data show how tumour-initiating mutations drive clinical behaviour by subtly biasing multiple evolutionary processes. Validation in other tumour types is underway.

Citation Format: Adriana Salcedo, John D. Watson, Hilary Racher, Diane Rushlow, Shadrielle Melijah G. Espiritu, Doroto H. Sendorek, Stephenie D. Prokopec, Donco Matveski, Fouad Yousif, Julie Livingstone, Brenda L. Gallie, Paul C. Boutros. Oncogenes and tumour-suppressors drive differential retinoblastoma evolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3771.

Activation of hedgehog signaling associates with early disease progression in chronic lymphocytic leukemia

Targeted sequencing of 103 leukemia-associated genes in leukemia cells from 841 treatment-naive patients with chronic lymphocytic leukemia (CLL) identified 89 (11%) patients as having CLL cells with mutations in genes encoding proteins that putatively are involved in hedgehog (Hh) signaling. Consistent with this finding, there was a significant association between the presence of these mutations and the expression of GLI1 (χ2 test, P < .0001), reflecting activation of the Hh pathway. However, we discovered that 38% of cases without identified mutations also were GLI1+ Patients with GLI1+ CLL cells had a shorter median treatment-free survival than patients with CLL cells lacking expression of GLI1 independent of IGHV mutation status. We found that GANT61, a small molecule that can inhibit GLI1, was highly cytotoxic for GLI1+ CLL cells relative to that of CLL cells without GLI1. Collectively, this study shows that a large proportion of patients have CLL cells with activated Hh signaling, which is associated with early disease progression and enhanced sensitivity to inhibition of GLI1.

Regional perturbation of gene transcription is associated with intrachromosomal rearrangements and gene fusion transcripts in high grade ovarian cancer

Genomic rearrangements are a hallmark of cancer biology and progression, allowing cells to rapidly transform through alterations in regulatory structures, changes in expression patterns, reprogramming of signaling pathways, and creation of novel transcripts via gene fusion events. Though functional gene fusions encoding oncogenic proteins are the most dramatic outcomes of genomic rearrangements, we investigated the relationship between rearrangements evidenced by fusion transcripts and local expression changes in cancer using transcriptome data alone. 9,953 gene fusion predictions from 418 primary serious ovarian cancer tumors were analyzed, identifying depletions of gene fusion breakpoints within coding regions of fused genes as well as an N-terminal enrichment of breakpoints within fused genes. We identified 48 genes with significant fusion-associated upregulation and furthermore demonstrate that significant regional overexpression of intact genes in patient transcriptomes occurs within 1 megabase of 78 novel gene fusions that function as central markers of these regions. We reveal that cancer transcriptomes select for gene fusions that preserve protein and protein domain coding potential. The association of gene fusion transcripts with neighboring gene overexpression supports rearrangements as mechanism through which cancer cells remodel their transcriptomes and identifies a new way to utilize gene fusions as indicators of regional expression changes in diseased cells with only transcriptomic data.

The molecular hallmarks and clinical consequences of tumor hypoxia in prostate cancer

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Background: Localised prostate cancers are classified into risk-groups using clinical measurements like grade and stage to inform treatment decisions. However, these groupings are imprecise: ~30% of intermediate-risk patients suffer relapse of their disease despite precision image-guided radiotherapy or radical prostatectomy. One reason for this variability in response to treatment is the underlying cellular and molecular heterogeneity of tumours. Prostate tumour cells exist within a microenvironment characterized by gradients of oxygen levels and prostate tumours with low levels of oxygen (hypoxia) have poor clinical outcomes. Methods: Hypoxia was measured using multiple mRNA-based signatures. We examined 548 patients with localised prostate cancer and statistically assessed the association of hypoxia with copy-number alterations (CNAs), single-nucleotide variants (SNVs), genomic rearrangements, focal genomic events ( i.e. kataegis, chromothripsis), telomere length, clinical indices ( i.e. grade, stage) and subclonal architecture. Results: Elevated hypoxia was associated with allelic loss of PTEN, higher rates of chromothripsis and intraductal and cribriform carcinoma (IDC-CA). To translate these findings into a biomarker for prostate cancer precision medicine, we integrated tumour microenvironmental data with genomic and pathological information to stratify patients into distinct prognostic groups. Patients with localized prostate cancer that have polyclonal tumours with elevated hypoxia, allelic loss of PTEN and IDC-CA were at the highest risk of rapid biochemical failure (P = 3.48 x10-3, Logrank test) and metastasis (P = 4.61 x 10-3, Logrank test), even after controlling for T-category, Gleason score and pre-treatment PSA. Conclusions: These data suggest that the aggressiveness of prostate cancers is driven by the interplay of the tumour microenvironment, tumour evolutionary trajectories and its genomic mutational profile.

Molecular landmarks of tumor hypoxia across cancer types

Many primary-tumor subregions have low levels of molecular oxygen, termed hypoxia. Hypoxic tumors are at elevated risk for local failure and distant metastasis, but the molecular hallmarks of tumor hypoxia remain poorly defined. To fill this gap, we quantified hypoxia in 8,006 tumors across 19 tumor types. In ten tumor types, hypoxia was associated with elevated genomic instability. In all 19 tumor types, hypoxic tumors exhibited characteristic driver-mutation signatures. We observed widespread hypoxia-associated dysregulation of microRNAs (miRNAs) across cancers and functionally validated miR-133a-3p as a hypoxia-modulated miRNA. In localized prostate cancer, hypoxia was associated with elevated rates of chromothripsis, allelic loss of PTEN and shorter telomeres. These associations are particularly enriched in polyclonal tumors, representing a constellation of features resembling tumor nimbosus, an aggressive cellular phenotype. Overall, this work establishes that tumor hypoxia may drive aggressive molecular features across cancers and shape the clinical trajectory of individual tumors.

Abstract 2432: The genomic consequences of tumor hypoxia in human cancers

Introduction: Localized prostate cancers are classified into risk-groups using clinical measurements like grade and stage to inform treatment decisions. However, these groupings are imprecise: ~30% of intermediate-risk patients suffer relapse of their disease despite precision image-guided radiotherapy or radical prostatectomy. One reason for this variability in response to treatment is the underlying cellular and molecular heterogeneity of tumors. Prostate tumor cells exist within a microenvironment characterized by gradients of oxygen levels and prostate tumors with low levels of oxygen (hypoxia) have poor clinical outcomes.

Methods and Results: To understand the correlates of hypoxia in cancer we conducted a pan-cancer analysis of copy number alterations (CNAs) and single nucleotide variants (SNVs) across 19 cancer types. We measured hypoxia using multiple mRNA-based signatures and discovered numerous CNAs and SNVs enriched or depleted in hypoxic tumors, highlighting the role of hypoxia in shaping the genomic landscape of multiple tumor types. Next, we examined 548 patients with localized prostate cancer and statistically assessed the association of hypoxia with CNAs, SNVs, genomic rearrangements, focal genomic events (i.e. kataegis, chromothripsis), telomere length, clinical indices (i.e. grade, stage) and subclonal architecture. Tumor hypoxia is associated with specific CNAs and SNVs in prostate cancer driver genes. To translate these findings into a biomarker for prostate cancer precision medicine, we integrated tumor microenvironmental data with genomic and pathological information to stratify patients into distinct prognostic groups.

Impact: These data suggest that the aggressiveness of cancers is driven by the interplay of the tumor microenvironment and its genomic mutational profile.

Citation Format: Vinayak Bhandari, Shadrielle M. Espiritu, Lydia Y. Liu, Emilie Lalonde, Takafumi N. Yamaguchi, Lawrence E. Heisler, Julie Livingstone, Vincent Huang, Yu-Jia Shiah, Veronica Y. Sabelnykova, Fouad Yousif, Melvin L. Chua, Michael Fraser, Theodorus van der Kwast, Paul C. Boutros, Robert G. Bristow. The genomic consequences of tumor hypoxia in human cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2432.

Cribriform and intraductal prostate cancer are associated with increased genomic instability and distinct genomic alterations

BACKGROUND

Invasive cribriform and intraductal carcinoma (CR/IDC) is associated with adverse outcome of prostate cancer patients. The aim of this study was to determine the molecular aberrations associated with CR/IDC in primary prostate cancer, focusing on genomic instability and somatic copy number alterations (CNA).

METHODS

Whole-slide images of The Cancer Genome Atlas Project (TCGA, N = 260) and the Canadian Prostate Cancer Genome Network (CPC-GENE, N = 199) radical prostatectomy datasets were reviewed for Gleason score (GS) and presence of CR/IDC. Genomic instability was assessed by calculating the percentage of genome altered (PGA). Somatic copy number alterations (CNA) were determined using Fisher-Boschloo tests and logistic regression. Primary analysis were performed on TCGA (N = 260) as discovery and CPC-GENE (N = 199) as validation set.

RESULTS

CR/IDC growth was present in 80/260 (31%) TCGA and 76/199 (38%) CPC-GENE cases. Patients with CR/IDC and ≥ GS 7 had significantly higher PGA than men without this pattern in both TCGA (2.2 fold; p = 0.0003) and CPC-GENE (1.7 fold; p = 0.004) cohorts. CR/IDC growth was associated with deletions of 8p, 16q, 10q23, 13q22, 17p13, 21q22, and amplification of 8q24. CNAs comprised a total of 1299 gene deletions and 369 amplifications in the TCGA dataset, of which 474 and 328 events were independently validated, respectively. Several of the affected genes were known to be associated with aggressive prostate cancer such as loss of PTEN, CDH1, BCAR1 and gain of MYC. Point mutations in TP53, SPOP and FOXA1were also associated with CR/IDC, but occurred less frequently than CNAs.

CONCLUSIONS

CR/IDC growth is associated with increased genomic instability clustering to genetic regions involved in aggressive prostate cancer. Therefore, CR/IDC is a pathologic substrate for progressive molecular tumour derangement.

Targeted sequencing in a phase III trial of luminal breast cancer: Identification of novel targets

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Background: The International Cancer Genome Consortium and The Cancer Genome Atlas have had a global transformative impact on our understanding of cancer. These programs have mapped the genomic landscape of common and rare tumors setting the scene for a comprehensive change in the approach to cancer diagnosis and treatment. However, the task remains incomplete until these mutational events are linked to clinical outcomes in the context of current therapeutic intervention to drive future stratified medicine approaches. Methods: We performed targeted sequencing in patients from the Tamoxifen Exemestane Adjuvant Multicentre trial. DNA was extracted and a 101 gene panel analysed using a novel mutation calling pipeline. Both a priori and machine learning analyses were performed using distant recurrence free survival as the primary endpoint. Results: In 1,491 successfully analyzed samples 1,070 (71.76%) samples exhibited at least one single nucleotide mutation (range 0-94, 1.828+/-0.133, mean+/-s.e.). 98/101 genes were mutated in at least one patient. Only variants in PIK3CA, TP53, MLL3, CDH1 were detected in 5% or more of samples. Twenty genes were associated with increased risk of recurrence in multivariate analyses corrected for clinic-pathological variables, 50% of these genes were involved in transcriptional regulation or RNA/protein processing. In a multivariate analysis, two combined signalling modules were independently prognostic for residual risk following hormone therapy (HRvalidation 3.10 95%CI 1.78-5.40 and HRvalidation 2.70 95%CI 1.57-4.64). Conclusions: We successfully performed a signalling pathway-based targeted sequencing analysis within predefined signalling modules. In supervised and unsupervised analyses we identified multiple signalling cassettes linked to poor outcome in patients with ER+ve breast cancers treated with modern endocrine therapy in the context of a phase III clinical trial. These results identify novel candidates as targets to treat endocrine refractory breast cancers.

A four gene signature predicts benefit from anthracyclines: evidence from the BR9601 and MA.5 clinical trials

Chromosome instability (CIN) in solid tumours results in multiple numerical and structural chromosomal aberrations and is associated with poor prognosis in multiple tumour types. Recent evidence demonstrated CEP17 duplication, a CIN marker, is a predictive marker of anthracycline benefit. An analysis of the BR9601 and MA.5 clinical trials was performed to test the role of existing CIN gene expression signatures as predictive markers of anthracycline sensitivity in breast cancer. Univariate analysis demonstrated, high CIN25 expression score was associated with improved distant relapse free survival (DRFS) (HR: 0.74, 95% CI 0.54-0.99, p = 0.046). High tumour CIN70 and CIN25 scores were associated with aggressive clinicopathological phenotype and increased sensitivity to anthracycline therapy compared to low CIN scores. However, in a prospectively planned multivariate analysis only pathological grade, nodal status and tumour size were significant predictors of outcome for CIN25/CIN70. A limited gene signature was generated, patients with low tumour CIN4 scores benefited from anthracycline treatment significantly more than those with high CIN4 scores (HR 0.37, 95% CI 0.20-0.56, p = 0.001). In multivariate analyses the treatment by marker interaction for CIN4/anthracyclines demonstrated hazard ratio of 0.35 (95% CI 0.15-0.80, p = 0.012) for DRFS. This data shows CIN4 is independent predictor of anthracycline benefit for DRFS in breast cancer.

The first record of Centrocestus formosanus (Nishigori, 1924) (Digenea: Heterophyidae) in Egypt

The life cycle of Centrocestus formosanus (Digenea: Heterophyidae) was to be successfully completed in the laboratory in the present study. Hundreds of the thiarid snail, Melanoides tuberculata, were collected from the main water course Mansouriya Canal, Giza Governorate, Egypt. The snails were individually exposed to artificial light to determine possible infection with trematode larvae. Fifteen snails were found infected with opthalmopleurolophocercous cercariae (infection index of 1.97). These opthalmopleurolophocercous cercariae shedded from snails were collected and placed in an aquarium with fish intermediate host, Gambusia affinis, to obtain metacercariae encysted in the gills. The gills with metacercariae were fed to albino rats, Rattus norvegicus, to obtain the adult worms. Adult worms were recovered in the small intestine of rats at 7 days after infection and they were identified as Centrocestus formosanus based on the morphological characteristics and the comparison with the previous descriptions in the literature. They were small, 518 × 324 μm in average size and had characteristic 32 circumoral spines around the oral sucker. The morphological characteristics of the developmental stages, from cercariae to adults, of this heterophyid fluke were given here. Therefore, the presence of this fluke is to be confirmed for the first time in Egypt by the present study.

Spatial genomic heterogeneity within localized, multifocal prostate cancer

Herein we provide a detailed molecular analysis of the spatial heterogeneity of clinically localized, multifocal prostate cancer to delineate new oncogenes or tumor suppressors. We initially determined the copy number aberration (CNA) profiles of 74 patients with index tumors of Gleason score 7. Of these, 5 patients were subjected to whole-genome sequencing using DNA quantities achievable in diagnostic biopsies, with detailed spatial sampling of 23 distinct tumor regions to assess intraprostatic heterogeneity in focal genomics. Multifocal tumors are highly heterogeneous for single-nucleotide variants (SNVs), CNAs and genomic rearrangements. We identified and validated a new recurrent amplification of MYCL, which is associated with TP53 deletion and unique profiles of DNA damage and transcriptional dysregulation. Moreover, we demonstrate divergent tumor evolution in multifocal cancer and, in some cases, tumors of independent clonal origin. These data represent the first systematic relation of intraprostatic genomic heterogeneity to predicted clinical outcome and inform the development of novel biomarkers that reflect individual prognosis.

Abstract P2-05-05: A four gene signature predicts anthracycline benefit: Evidence from the BR9601 and MA5 breast cancer trials

Background: Chromosome instability (CIN) in solid tumours is associated with poor prognosis and results in numerical and structural chromosomal aberrations. Recent evidence from both the BR9601 and MA.5 trials has demonstrated CEP17 duplication as a predictive marker of anthracycline benefit. CIN25 and CIN70 gene expression profiles have previously been published and predict survival response. An analysis of the BR9601 and MA5 clinical trials was performed to test the role of CIN gene expression signatures as a marker of anthracycline sensitivity.

Methods: RNA was extracted from patients in both the BR9601 and MA5 studies and analysed through Nanostring technology. Log-rank analyses explored the prognostic values of the signatures on distant relapse-free survival (DRFS). Cox-regression models tested independent prognostic value on DRFS in the presence of treatment, age, tumour size, nodal status, ER status and grade, and treatment by marker interactions.

Results: Of the 761 samples available from the BR9601 and MA5 cohorts we successfully analysed 703 (92.4%). High CIN25 and CIN70 scores were associated with age (p&lt;0.0001), grade (p0.0001), PgR negativity (p&lt;0.0001) and ER negativity (p&lt;0.0001). In univariate analysis, high CIN25 score was associated with decreased DRFS (HR: 0.74, 95% CI 0.54-0.99, p=0.046). In a multivariate analysis with adjustment for size, nodal status, ER, pathological grade, HER2, CIN25, treatment and treatment by marker only pathological grade, nodal status and tumour size were significant predictors of outcome.

A more limited set of genes that reflected CIN was established by examining the expression profile of the genes and clustering them. The combined cohort was split into a 60% training and 40% validation set. The area under the curve (AUC) was calculated and the gene signature with the greatest AUC was selected and termed CIN4. Patients with low CIN4 score benefited from anthracycline treatment compared to those that had high CIN4 score (HR 2.72, 95% CI 1.48-5.02, p=0.001). No significant benefit with CMF treatment was observed in (HR: 1.02, 95% CI 0.58-1.82, p=0.92). After multivariate analysis the treatment by marker interaction for CIN4 had a hazard ratio of 2.10 (95% CI 2.18-30.38, p= 0.001).

Conclusion: High CIN70 and CIN25 scores were associated with an aggressive phenotype and showed a potential increased sensitivity to anthracycline therapy compared to those with low CIN scores. CIN4 was an independent predictor of anthracycline benefit for DRFS. However, further work in larger patient cohorts such as NEAT is warranted.

Citation Format: Melanie Spears, Nicola S Lyttle, Fouad Yousif, Alison F Munro, Christopher Twelves, Kathleen I Pritchard, Mark N Levine, Lois Shepherd, John MS Bartlett. A four gene signature predicts anthracycline benefit: Evidence from the BR9601 and MA5 breast cancer trials [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-05-05.

Experimental evaluation of Candonocypris novaezelandiae (Crustacea: Ostracoda) in the biocontrol of Schistosomiasis mansoni transmission

OBJECTIVE

To test Candonocypris novaezelandiae (Baird) (C. novaezelandiae), sub-class Ostracoda, obtained from the Nile, Egypt for its predatory activity on snail, Biomphalaria alexandrina (B. alexandrina), intermediate host of Schistosoma mansoni (S. mansoni) and on the free-living larval stages of this parasite (miracidia and cercariae).

METHODS

The predatory activity of C. novaezelandiae was determined on B. alexandrina snail (several densities of eggs, newly hatched and juveniles). This activity was also determined on S. mansoni miracidia and cercariae using different volumes of water and different numbers of larvae. C. novaezelandiae was also tested for its effect on infection of snails and on the cercarial production.

RESULTS

C. novaezelandiae was found to feed on the eggs, newly hatched and juvenile snails, but with significant reduction in the consumption in the presence of other diet like the blue green algae (Nostoc muscorum). This ostracod also showed considerable predatory activity on the free-living larval stages of S. mansoni which was affected by certain environmental factors such as volume of water, density of C. novaezelandiae and number of larvae of the parasite.

CONCLUSIONS

The presence of this ostracod in the aquatic habitat led to significant reduction of snail population, infection rate of snails with schistosme miracidia as well as of cercarial production from the infected snails. This may suggest that introducing C. novaezelandiae into the habitat at schistosome risky sites could suppress the transmission of the disease.

Description of two new cercariae (an echinostome cercaria and a xiphidiocercaria) procured from Biomphalaria pfeifferi (Krauss) from Nigeria

During parasitological examination of Biomphalaria pfeifferi snails obtained from Niger state (Nigeria), 2 new types of cercariae were found. They are identified to the level of referring to the major group and described here for the first time. They were examined viable and stained with vital stains as well as fixed in 70% alcohol. They were drawn with a camera lucida and photographed. They are identified as an echinostome cercaria and a xiphidiocercaria. The echinostome is characterized by having a ventral sucker almost double in size the oral one. It has a semicircular structure located beyond the oral sucker. Three pairs of penetration glands are found at the anterior portion of the body. The number of collar spines is relatively large (44-46). The flame cellsare 17 x 2 in number. Two main lateral excretory ducts extend anteriorly, form two typical echinostome loops then pass posteriorly to open together in a diverticulated excretory vesicle. Its tail is relatively long and flattened with 3 fin folds. The tail (640 μm) is longer than the body (475 μm). The xiphidiocercaria belongs to the "ornatae" group. It is relatively small (180.5 x 110 μm) with a long stylet (30 μm). Its oral sucker is one and half times the size of the ventral sucker. Two excretory ducts extend posteriorly in both sides and become dilated and unite to open in a circular excretoryvesicle. Tail is slender shorter than the body and has a dorso-ventral fin fold.

Identification of pre-leukaemic haematopoietic stem cells in acute leukaemia

In acute myeloid leukemia (AML), the cell of origin, nature and biological consequences of initiating lesions and order of subsequent mutations remain poorly understood, as AML is typically diagnosed without observation of a pre-leukemic phase. Here, highly purified hematopoietic stem cells (HSC), progenitor and mature cell fractions from the blood of AML patients were found to contain recurrent DNMT3a mutations (DNMT3a^mut) at high allele frequency, but without coincident NPM1 mutations (NPM1c) present in AML blasts. DNMT3a^mut-bearing HSC exhibited multilineage repopulation advantage over non-mutated HSC in xenografts, establishing their identity as pre-leukemic-HSC (preL-HSC). preL-HSC were found in remission samples indicating that they survive chemotherapy. Thus DNMT3a^mut arises early in AML evolution, likely in HSC, leading to a clonally expanded pool of preL-HSC from which AML evolves. Our findings provide a paradigm for the detection and treatment of pre-leukemic clones before the acquisition of additional genetic lesions engenders greater therapeutic resistance.

Schistosoma mansoni cercarial host location and infection under simulated natural conditions in Egypt

This study was performed in water ditches under simulated natural conditions in Egypt to elucidate the effect of various environmental factors on Schistosoma mansoni cercarial host location and infection of the definitive host (using albino mice). Evaluation of these factors was dependent on both infection rate of exposed mice as well as the schistosome worm load under the same experimental conditions. The seasonal water temperature proved to be a very important factor and this was proven by the infection rate of mice and the worm load recovered were lower in January and April (16 degrees C and 22 degrees C midday water temperature) and much higher in July and October (29 degrees C and 25 degrees C). The daytime factor is similarly important as temperature illustrated by the schistosome infection of mice groups exposed at 8-10 am was much higher than in groups exposed between 1 pm and 3pm (p < 0.001). The greatest infection rate of mice and worm load were obtained when the shedding snails were close to the exposed group of mice. Both criteria increased with the increase of cercarial density in the water. The length of exposure period is also an extremely important factor for schistosome infection, being highest 87.5% (p < 0.001) in3 hours exposure period. Infection rate was found to be 88.2% and 55.6% of shedding snails were located at water surface and midway to the bottom, respectively, and no infection occurred when located at the bottom. The schistosome infection of mice decreased in presence of increasing density of the floating plant Eichhornia crassipes in the ditch water, but low condensation of the submersed plant Ceratophyllum demersum appeared to have stimulating effect.

Abstract 2003: A molecular portrait of potentially curable prostate cancer

Intermediate risk prostate cancer (CaP) with Gleason score (GS) of 7 show up to 100x variability in genetic instability. As CaP is multifocal and likely multiclonal, there is a need to characterize heterogeneity for patient stratification, which would increase the ability to act on genomic information by adding adjuvant therapies to offset systemic occult metastases that currently limit cure in ∼30% of patients. Individual genetic portraits could be used to improve cure on combined clinical-molecular staging criteria.

We undertook a pilot study to assess the genetic heterogeneity of potentially curable GS=7 CaP. We selected 10 men with GS=7 CaP; 5 treated with external beam radiotherapy (frozen pre-treatment biopsies) and 5 treated with radical prostatectomy (RadP, frozen tumour). Additionally, DNA from 18 distinct formalin-fixed, paraffin-embedded (FFPE) foci from the 5 RadP were analysed. Each of these 28 foci were subjected to whole-genome sequencing (WGS) and OncoScan SNP arrays to yield comprehensive genetic profiles. mRNA expression was evaluated on frozen RadP by microarray. Germline DNA from whole-blood was also analysed.

Following independent pathology reviews and manual macro-dissection of tumour areas of ≥70% cellularity, WGS (≥50x tumour, ≥30x germline) was performed on as little as 50 ng genomic DNA, and OncoScan arrays were performed using as little as 30ng DNA using either amplified or innate genomic DNA. Regions of CaP in FFPE RadP were recorded using a tissue map to identify independent malignant foci, and ERG immunostaining was performed to assist in the identification. In cases where ERG-positive and -negative foci were adjacent, ERG staining was repeated on an un-stained slide to confirm separate foci based on 3D multi-section analyses. ERG fusion status was also assessed in frozen samples by aCGH or IHC.

Validation of SNVs via SNP array and deep-resequencing showed ∼99% accuracy. Tumour cellularity was estimated using Qpure and was &gt;60% for all samples. Phylogenetic techniques were used to demonstrate clear multi-clonality in two tumours. Across all tumours, ∼50% of SNVs were specific to an individual tumour-region. Phylogenies were confirmed with both SNVs and CNAs, but CNAs generally exhibited greater concordance amongst different regions of the same tumour. Some previously observed recurrent mutations were previously identified as recurrent in CaP (e.g. SPOP), and the overall mutation rate for intermediate-risk CaP was only somewhat below that reported for castrate-resistant disease (11,230 somatic SNVs per tumour).

Our studies support the concept that a complete characterization of inter- and intra-CaP heterogeneity is possible in fresh and archival tissues; the latter is important for correlations to clinical outcome. These approaches can then be streamlined for high-throughput analyses within personalized medicine laboratories leading to “point of care” molecular tests and individualization of therapy.

Citation Format: Michael E. Fraser, Richard de Borja, Dominique Trudel, Nicholas J. Harding, Pablo H. Hennings-Yeomans, Alice Meng, Emilie R. Lalonde, Andrew Brown, Natalie S. Fox, Taryne Chong, Amin Zia, Michelle Sam, Jianxin Wang, Michelle A. Chan-Seng-Yue, Jeremy Johns, Lee Timms, Nicholas Buchner, Ada Wong, Fouad Yousif, Rob Denroche, Gaetano Zafarana, Maud HW Starmans, Hanbert Chen, Shaylan Govind, Francis Nguyen, Melania Pintilie, Neil Fleshner, Stanislav Volik, Lakshmi Muthuswamy, Colin C. Collins, Thomas J. Hudson, Lincoln D. Stein, Timothy Beck, John D. McPherson, Theodorus van der Kwast, Paul C. Boutros, Rob G. Bristow. A molecular portrait of potentially curable prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2003. doi:10.1158/1538-7445.AM2013-2003

Schistosomes: challenges in compound screening

Major progress in studying the biology of schistosomes had been achieved since the late 1960s with the successful laboratory cultivation of the parasite's life cycle stages in the vertebrate (in vivo animal models) and snail hosts. This was followed by establishment of in vitro culture techniques for cultivation of the different life cycle stages to understand the mechanisms regulating the parasite's growth, development, transformation, pathogenicity and survival, with prospects to develop and identify relevant candidate diagnostic, immunological and chemotherapeutic targets. Chemotherapeutic measures have been the mainstay in the control of schistosomiasis. The use of praziquantel, a relatively safe and orally administered drug, in targeted or mass treatment programmes had significantly reduced the prevalence of schistosomiasis in disease-endemic countries. However, with only one drug of choice for treatment, parasite resistance remains a major concern. Thus, new drug discovery against schistosomes cannot be overemphasised. Undoubtedly, this will require an integrated system that includes not only rational chemical synthesis and lead optimisation, but also appropriate drug screening strategies. This paper reviews the present state of in vitro and in vivo drug screening strategies against schistosomes. It also highlights the best practices for compound screening in the TDR-designated compound screening centres and details some of the challenges involved in in vitro and in vivo compound screening.

Contribution to in vitro screening of Egyptian plants for schistosomicidal activity

CONTEXT

This study is a continuation of our previous work in which a bioassay screening of 346 methanol extracts from 281 Egyptian plant species was carried out for in vitro schistosomicidal activity.

OBJECTIVE

Another 309 methanol extracts from 278 plant species were subjected to the bioassay screening using the same technique on viable Schistosoma mansoni Sambon (Schistosomatidae) mature worms in specialized culture medium (Roswell Park Memorial Institute medium 1640) in a trial to discover a source for a schistosomiasis drug from Egyptian flora.

MATERIAL AND METHODS

The methanol plant extracts were tested in vitro against viable S. mansoni mature worms in culture medium. Viability of worms was examined after exposure to 100 μg/ml of the extract in the medium for 24 h. Negative (dimethyl sulfoxide) and positive (praziquantel) controls were simultaneously used. Extracts showing schistosomicidal activity were further subjected to determination of their (Lethal concentration) LC₅₀ and LC₉₀ values.

RESULTS

Confirmed in vitro antischistosomal activity was found in 42 extracts. Of these, 14 plant species possessed considerably high antischistosomal activity (LC₅₀ ≤ 15 µg/ml), viz. Callistemon viminalis (Soland. Ex Gaertn) Cheel, C. rigidus R.Br., C. speciosus (Sims.) DC, C. citrinus Stapf, Eucalyptus citriodora Hook, E. rostrata Dehnh., Eugenia edulis Vell, E. javanica Lam syn. Syzygium samarangense (Blume) Merril, Melaleuca leucadendron (L.) L., M. stypheloides Sm. (all belong to Myrtaceae), Cryptostegia grandiflora R.Br. (Asclepiadaceae), Zilla spinosa (L.) Prantl (Cruciferae), Ficus trijuja L. (Moraceae) and Fagonia mollis Delile (Zygophylacae).

DISCUSSION AND CONCLUSION

These species may represent additional natural sources of bioactive material that deserve further investigation for drug discovery against schistosomiasis.

Abstract 3184: Whole genome sequencing of low-input fresh frozen prostate cancer biopsies

Prostate cancer is the most commonly diagnosed malignancy among men in the United States. Due to an aging population, prostate cancer incidence has been increasing, with an estimated 200,000 men being diagnosed in 2010 and more than 32,000 deaths resulting from this disease. Better predictors of patient prognosis and treatment outcome are required to individualize prostate cancer treatment. High-throughput genomic sequence-based approaches offer a unique opportunity to identify biomarkers of disease-progression, thereby enabling more individualized therapy. The Canadian Prostate Cancer Genome Network (CPC-GENE) is an outcomes-based initiative that will sequence 500 specimens from 350 prostate cancer patients over a 5-year time span. Previously, whole genome sequencing efforts from biopsy specimens have been hindered by insufficient quantities of extracted DNA required as input for sequencing library construction. As a proof of concept to demonstrate the ability to sequence low input amounts of DNA from prostate biopsies, whole genome sequencing has been initiated for 50 prostate tumor biopsy samples along with their matched blood-derived reference sample. An on-bead sample preparation protocol was optimized using decreasing quantities of input DNA and used to construct sequencing libraries from as low as 100ng of DNA derived from macrodissected fresh frozen prostate biopsies (&gt;70% cellularity). Sequencing is performed on the Illumina HiSeq 2000 platform to generate coverage depths of 50x for tumor samples and 30x for reference samples. Following alignment using NovoAlign and variant-calling using GATK, we compared our results to genotyping-array results generated using the Affymetrix OncoScan platform. Single-nucleotide variants detected using arrays were validated &gt;99% of the time by sequence data, confirming that the use of a low-input library did not hinder mutation detection. Sequencing does not exhibit significant genome-wide coverage biases, and CNV calls were compared between the genotyping arrays and the next-generation sequencing data. Outcomes from the sequencing and analysis of the initial 50 sample sets will similarly be applied over a 5-year period to characterize an additional 450 prostate specimens. The ability to whole genome sequence specimens where minimal amounts of extracted DNA exist presents new opportunities to sequence many samples previously deemed unusable, while also providing encouraging prospects for whole genome sequencing applications for future studies using biopsy specimens.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3184. doi:1538-7445.AM2012-3184

Screening of marine extracts for schistosomicidal activity in vitro. Isolation of the triterpene glycosides echinosides A and B with potential activity from the Sea Cucumbers Actinopyga echinites and Holothuria polii

CONTEXT

Praziquantel (PZQ) is the drug available for the treatment of schistosomiasis. The reported reduced cure rates, the failure of treatment after PZQ administration in patients and the existence of resistant parasite strains, reinforce the need to rapidly discover new effective molecules against Schistosoma parasite.

OBJECTIVE

To screen the methanol extracts of 79 marine organisms for their schistosomicidal activities against Schistosoma mansoni adult worms in vitro and perform bio-assay directed chromatography for the most active extracts to isolate the active compounds.

MATERIALS AND METHODS

Screening of the marine organisms and bio-assay directed chromatography of the most active extracts together with identification of the active isolates using 1D and 2D NMR analysis, were investigated.

RESULTS

RESULTS indicated that the isolates echinosides A and B from the sea cucumbers Actinopyga echinites Jaeger and Holothuria polii Delle Chiaie (Holothuriidae) were highly active. Their LC(50) values were equal to 0.19 μg/ml and 0.27 μg/ml, respectively. Detailed (1)HNMR data for echinosides A and B are reported here for the first time.

DISCUSSION AND CONCLUSION

These findings demonstrate that the isolated echinosides possess potential in vitro schistosomicidal activity against S. mansoni adult worms. Therefore, echinosides are promising as lead compounds for the development of new schistosomicidal agents.

Schistosomicidal and molluscicidal activities of aminoalkylamino substituted neo- and norneocryptolepine derivatives

CONTEXT

The cryptolepines originate from the roots of the climbing shrub Cryptolepis sanguinolenta (Lindi) Schitr(Periplocaeae) which is used in Central and West Africa in traditional medicine for the treatment of malaria.

OBJECTIVES

Evaluation for the first time of a series of chloro- and aminoalkylamino derivatives of neo- and norneocryptolepines for potential schistosomicidal and molluscicidal activities.

MATERIALS AND METHODS

A series of chloro- and aminoalkylamino substituted neo- and norneocryptolepine derivatives were synthesized. They were tested in vitro against viable Schistosoma mansoni Sambon mature worms in culturemedium with fetal serum and antibiotics and in dechlorinated water against the snail vector Biomphalaria alexandrina Ehrenberg. Active compounds were further subjected to determination of their IC50 values.

RESULTS

Results showed that six neocryptolepine and two norneocryptolepine derivatives had in vitro schistosomicidal activity on Egyptian and Puerto Rican strains of S. mansoni. The most effective derivative (2-chloro-5-methyl-N-(2-morpholin-4-ethyl)-5H-indolo[2,3b]quinoline-11-amine) has IC50 and IC90 1.26 and 4.05 μM and 3.54 and 6.83 μM with the Egyptian and Puerto Rican strains of Schistosoma, respectively. All eight derivatives showed molluscicidal activity against the vector snail B. alexandrina. The most active compound (2-chloro-11-(4-methylpiperazin-1-yl)-6H-indolo[2,3-b] quinoline) has LC50 0.6 and LC90 3.9 ppm after 24 h.

DISCUSSION AND CONCLUSIONS

The findings demonstrate that introducing chloro- and aminoalkylamino side chain initiated both schistosomicidal and molluscicidal activities in these derivatives. The structure–activity relationship of this series of compounds is discussed.

Retention of forearm plates

Most surgeons favour removing forearm plates in children. There is, however, no long-term data regarding the complications of retaining a plate. We present a prospective case series of 82 paediatric patients who underwent plating of their forearm fracture over an eight-year period with a minimum follow-up of two years. The study institution does not routinely remove forearm plates. A total of 116 plates were used: 79 one-third tubular plates and 37 dynamic compression plates (DCP). There were 12 complications: six plates (7.3%) were removed for pain or stiffness and there were six (7.3%) implant-related fractures. Overall, survival of the plates was 85% at 10 years. Cox regression analysis identified radial plates (odds ratio (OR) 4.4, p = 0.03) and DCP fixation (OR 3.2, p = 0.02) to be independent risk factors of an implant-related fracture. In contrast ulnar plates were more likely to cause pain or irritation necessitating removal (OR 5.6, p = 0.04).

The complications associated with retaining a plate are different, but do not occur more frequently than the complications following removal of a plate in children.

Origin and diversification of the human parasite Schistosoma mansoni

Schistosoma mansoni is the most widespread of the human-infecting schistosomes, present in 54 countries, predominantly in Africa, but also in Madagascar, the Arabian Peninsula, and the Neotropics. Adult-stage parasites that infect humans are also occasionally recovered from baboons, rodents, and other mammals. Larval stages of the parasite are dependent upon certain species of freshwater snails in the genus Biomphalaria, which largely determine the parasite's geographical range. How S. mansoni genetic diversity is distributed geographically and among isolates using different hosts has never been examined with DNA sequence data. Here we describe the global phylogeography of S. mansoni using more than 2500 bp of mitochondrial DNA (mtDNA) from 143 parasites collected in 53 geographically widespread localities. Considerable within-species mtDNA diversity was found, with 85 unique haplotypes grouping into five distinct lineages. Geographical separation, and not host use, appears to be the most important factor in the diversification of the parasite. East African specimens showed a remarkable amount of variation, comprising three clades and basal members of a fourth, strongly suggesting an East African origin for the parasite 0.30-0.43 million years ago, a time frame that follows the arrival of its snail host. Less but still substantial variation was found in the rest of Africa. A recent colonization of the New World is supported by finding only seven closely related New World haplotypes which have West African affinities. All Brazilian isolates have nearly identical mtDNA haplotypes, suggesting a founder effect from the establishment and spread of the parasite in this large country.

Schistosomiasis in newly reclaimed areas in Egypt. 2--Patterns of transmission

The distribution, abundance and seasonality of infected Biomphalaria alexandrina and Bulinus truncatus were studied for 2 years (1992-1994) in two newly reclaimed areas, namely El Manayef and El-Morra areas located on both sides of Suez Canal near Ismailia City. The results confirm the occurrence of transmission of both Schistosoma mansoni and S. haematobium since infected snails of both species were recovered in these areas. This consequently proves that reclamation of parts of the desert utilizing Nile water had led to spread of schistosomiasis to these areas. Analysis of the data shows that the infected snails, especially B. alexandrina, were found clustered in a relatively few numbers of transmission sites and furthermore the greater majority of these sites were found located within a less number of transmission foci. This pattern of focality is clearly demonstrated by Geographical Information System (GIS) produced maps. Infected B. alexandrina snails fluctuated seasonally showing 2 peaks, a minor peak in August and a higher one in November. Only one peak of infected B. truncatus was recognized in July.

Schistosomiasis in newly reclaimed areas in Egypt. 1-distribution and population seasonal fluctuation of intermediate host snails

Two newly reclaimed areas located west & east of Suez Canal, namely El Manayef area and El Morra area, were studied for patterns of distribution and population seasonal fluctuation of Biomphalaria alexandrina and Bulinus truncatus, the intermediate host snails of Schistosoma mansoni and S. haematobium, respectively. In this study Geographic Information System (GIS) techniques were utilized for producing maps and analyzing the results. Habitats of the two vector snail species were categorized into suitability levels depending on the frequency with which snails were collected over a 12 months period. Data obtained from the most suitable habitats were only used for studying the seasonal fluctuation of snail population. The results showed that both study areas were almost similar in major physico-chemical parameters. However, oxygen content in canals was higher than in drains and conductivity was higher in drains than in canals. As regards snail distribution and density, most snails of both considered species were clustering in much fewer numbers of sites, more pronouncedly in the case of Biomphalaria than Bulinus. Population density of snails was significantly higher in El-Manayef area than in El-Morra area and in canals than in drains. Both species exhibited 2 population peaks/year, the peaks of Biomphalaria were in March-April & August in both study areas, while for Bulinus these peaks occurred in March-May and August in El-Manayef area and in May and March, respectively, in El-Morra area.

Compatibility of Biomphalaria alexandrina, Biomphalaria glabrata and a hybrid of both to seven strains of Schistosoma mansoni from Egypt

The susceptibility of Biomphalaria alexandrina, Biomphalaria glabrata and a hybrid snail of both, all obtained from natural habitats in Egypt, to infection with six human local strains of Schistosoma mansoni and a laboratory strain of human origin was determined. The infection rate, prepatent period, periodic cercarial production and duration of cercarial shedding were compared in all cases. The results showed that each of the three studied Biomphalaria snails had different rates of infection and different values of total periodic cercarial production with various strains of S. mansoni. However, the mean infection rate of all local S. mansoni strains was significantly much higher in B. alexandrina than each of B. glabrata and the hybrid snail, being 66%, 7.2% and 8.5%, respectively. Considering the mean of results of all local S. mansoni strains used, the longevity of cercariae-shedding B. glabrata and the hybrid snails was much longer than that of B. alexandrina, with high significant difference between them (P < 0.01), being 94.5, 103.3 & 69.1 days, respectively. The mean prepatent period of various S. mansoni strains showed no significant difference in the three Biomphalaria snails studied. The hybrid snail produced periodically (1 h stimulant twice weekly) more schistosome cercariae/snail (4,784.2) than B. glabrata (2,913.4 cercariae/snail) and the least production was in the case of B. alexandrina (1,397.2 cercariae/snail) (P < 0.05). The diurnal pattern of S. mansoni cercarial shedding was found to be similar for B. glabrata, B. alexandrina and the hybrid snail showing a peak of cercariae at the same time (9-10 a.m.).

Effect of six non-target snails on Schistosoma mansoni miracidial host finding and infection of Biomphalaria alexandrina under laboratory conditions

Six snail species naturally associated with Biomphalaria alexandrina, the snail host of Schistosoma mansoni in Egypt, were tested under standard laboratory conditions, for impact on miracidial host findings and infection of the snail host. These snails are the prosobranchs Melanoides tuberculata, Cleopatra bulimoides, Bellamys unicolor and Lanistes carinatus, the pulmonates Planorbis planorbis and Physa acuta. The tested snail ssp. reduced considerably the infection rate of Biomphalaria with S. mansoni especially at a ratio of 10 decoy snails to one Biomphalaria snail. The prosobranchs Melanoides, Cleopatra and Lanistes exhibited more reducing effect on Biomphalaria infection than Bellamya and the pulmonates Physa and Planorbis being 65.2%, 78.8%, 62.9%, 33.3%, 30.3% and 46.9%, respectively.

Invasion of the Nile Valley in Egypt by a hybrid of Biomphalaria glabrata and Biomphalaria alexandrina, snail vectors of Schistosoma mansoni

Two years (1996-1997) of systematic survey showed that a hybrid of Biomphalaria glabrata and Biomphalaria alexandrina has invaded the irrigation and drainage systems in the Nile Delta and the Valley nor the of El-Menya. However, the infestation of water courses by and the population density of this snail were variable in various localities. The infestation rate ranged between 7.1% in El-Fayoum Governorate and 52.6% in El-Dakahliya Governorate and the snail density from 2 snails/site to 69.7 snails/site in the same governorates, respectively. Comparing the survey results of the two study years in the sampling sites indicated that the hybrid snail has relatively increased in population density than B. alexandrina. The hybrid snail of B. glabrata and B. alexandrina was found alone in some sites, but was mostly associated with B. alexandrina. The results showed also that both Biomphalaria have almost the same major physicochemical requirements. However, the hybrid snails and B. alexandrina were found differently associated with aquatic snails and plants. The hybrid snail was found naturally infected with S. mansoni thus giving indication that it is presently participating in schistosomiasis mansoni transmission in Egypt.

Cercariometry in the study of Schistosoma mansoni transmission in Egypt

The recovery of Schistosoma mansoni cercariae was studied in experimental ditches and natural irrigation canals using a continuous operating centrifuge and a water suction sampling technique. Recovery of cercariae from static water in the ditches where caged infected Biomphalaria alexandrina snails were placed showed that cercariae recovered were more with increase of infected snails and decrease of water volume and were most abundant in the proximity of the snails which produced them. Shade or heavy vegetation cover reduced the recovery of cercariae. Results suggest also strong seasonal differences in diurnal patterns of cercarial recovery. An early morning peak with large number of cercariae occurred during hot weather while in cooler seasons cercariae appear in fewer numbers but persist for most of the day. Obtained information, beside contributing to knowledge of cercarial behaviour, should help to optimize taking water sample and consequently to increase efficiency of cercariometry techniques. In the natural irrigation system, cercariometry was significantly more sensitive in detecting transmission foci than snail sampling by a dip net.

Filtration, centrifugation and mouse exposure for the detection of schistosome cercariae in water

Three methods for detection of schistosome cercariae in water were studied under laboratory and simulated field conditions in Egypt. Water samples tested by filtration and centrifugation quantitatively reflected the density of cercariae in moderately turbid canal water (30 Nephelometry Turbidity Unites, NTU). When tested in waters of increasing turbidity, the centrifuge gave more consistent results than the filtration system. The centrifugation technique was more efficient in processing the water samples and took almost half the time of filtration. Mouse exposure was useful in detecting cercariae, but was not quantitative. However, there was a significant improvement in worm recovery when mice were more close together in the floatation device. Mouse exposure was also expensive and cumbersome to use. It appears from the present results that the technique of choice for further cercariometric work under Egyptian conditions may be centrifugation.

Biomphalaria glabrata: a new threat for schistosomiasis transmission in Egypt

This is the first report on the infestation of irrigation and drainage systems at Giza, Qalyoubiya and Kafr El Shiekh Governorates, with Biomphalaria glabrata (the snail host of Schistosoma mansoni in the new world). Identification of this snail species was based on morphometry of the shell, shape of the radular lateral teeth and presence of the characteristic renal ridge. B. glabrata snails collected from natural water courses in Egypt proved to be susceptible to a local strain of S. mansoni. These snails were infected by 52% versus 75% for Biomphalaria alexandrina (the only local host) under the same laboratory conditions. Meanwhile the periodic total cercarial production was higher in B. glabrata than in B. alexandrina (252 +/- 110 cercariae/snail versus 203 +/- 86 cercariae/snail, respectively). Differences in infection rate, length of schistosome incubation period, duration of cercarial shedding and cercarial production in various sizes of the two snail species are reported and discussed.

Population dynamics and schistosomal infection of Biomphalaria alexandrina in four irrigation canals in Egypt

The natural growth, reproductivity, mortality and schistosomal infection of Biomphalaria alexandrina, the snail vector of Schistosoma mansoni in Egypt, were studied for one year in four irrigation canals, namely El-Khassa and Radwan (Giza Governorate) and Sendebis and Sanafeer (Qalyoubiya Governorate). Radwan canal contains a considerably dense Biomphalaria population and three generations of snails (parents generation and autumn and spring generations) were recognized. Two phases of growth were distinguished in both autumn and spring generations, a faster phase followed by a slower one. The faster phase extends from January to May and from March to August in the autumn and spring generations, respectively. The daily mortality rate of snails was highest in the hot season (June--September) and lowest in the cold months (December--April). Continuous reproductivity of Biomphalaria snails was observed allover the year with highest values of reproduction index from November to March. Biomphalaria snails collected from El Khassa and Radwan canals were free of S. mansoni infection, while snails of Sanafeer canal carried patent infection in September and October. Prepatent infection was also found in Sanafeer canal in July and September and in Sendebis canal in September.

Ecology of Biomphalaria alexandrina the snail vector of Schistosoma mansoni in Egypt

The patterns of spreading and seasonal variation of population density of Biomphalaria alexandrina, the snail vector of Schistosoma mansoni in Egypt, in correlation with some environmental parameters were studied for 1988-1990 in four irrigation canals in Giza and Qalyoubiya Governorates. Results shown that the spreading patterns of snails along canals are changeable because of water current and irrigation activities. The snail population density showed two peaks, different in height, in April-May and November-December separated by two bottoms following the Winter Closure and during the hot summer season. The height of the peaks appears to be dependent on the extent of the "Winter Closure" and the prevailing water temperature. Two snail sampling tools, the dip-net and drag scoop, were used concurrently in this study. No considerable difference in sampling efficacy was recognized between these tools in the case of Biomphalaria. However, the dip-net appears to be more efficient in sampling other pulmonates while the drag scoop is more efficient in sampling prosobranchs. It is also realized that double sampling of 50% of sampling sites the next day should be satisfactory as a quality control system in snail population studies.

Helisoma duryi: its present range of distribution and implications with schistosomiasis snails in Egypt

The range of distribution of Helisoma duryi, a potential competitor to schistosomiasis snail vectors in Egypt, was determined in the south of Nile Delta. Results show that H. duryi was found in the River Nile, Geziret El Kerateyeen banks, Damietta and Rosetta Branches, Tawfiky and Menoufy Canals and their branches and Bassoussiya, Bahadiya and Sheshaa canals and their branches. Helisoma was found in all categories of canals and drains co-existing in various degrees with other snail species including schistosomiasis vectors (Bulinus truncatus and Biomphalaria alexandrina). The population density of H. duryi and associated B. truncatus, B. alexandrina and Physa acuta were studied for one year in three channels. Statistical analysis of results show that Helisoma has a significantly negative correlation with schistosomiasis vectors in these channels. Helisoma population showed a major peak in the warmest months of the year (July-August) thus showing recovery in population after "Winter Closure" later than Bulinus, Biomphalaria and Physa. Helisoma proved to be free of any natural trematode infection.

Effect of the molsidomine metabolite SIN-1 on coronary arteries and peripheral vessels of sheep with special reference to tolerance and endothelium

In vitro experiments on rings from coronary arteries, femoral arteries, and femoral veins of sheep were performed, and cumulative concentration-relaxation responses were established for glyceryl trinitrate (GTN) and the molsidomine metabolite SIN-1. Paired preparations of control and deendothelialized coronary artery rings were used, and the vessels were precontracted with different agonists at a concentration that elicited 30% of maximal contractions (EC-30). In coronary arteries, the responses for GTN and SIN-1 on normal and deendothelialized preparations were not significantly different. In coronary arteries preincubated with 0.44 mM GTN or SIN-1 to study tolerance development, there was a significant loss of efficacy to the relaxant effect of GTN, whereas the effect SIN-1 was essentially maintained. Femoral arteries and veins were readily relaxed with GTN. and SIN-1. In veins relaxation in relation to resting tone was much more pronounced than in coronary or femoral arteries. In conclusion, the molsidomine metabolite SIN-1 is a potent coronary and venous vasodilator that does not induce tolerance.