Mitochondrial DNAs provide insight into trypanosome phylogeny and molecular evolution

Background

Trypanosomes are single-celled eukaryotic parasites characterised by the unique biology of their mitochondrial DNA. African livestock trypanosomes impose a major burden on agriculture across sub-Saharan Africa, but are poorly understood compared to those that cause sleeping sickness and Chagas disease in humans. Here we explore the potential of the maxicircle, a component of trypanosome mitochondrial DNA to study the evolutionary history of trypanosomes.

Results

We used long-read sequencing to completely assemble maxicircle mitochondrial DNA from four previously uncharacterized African trypanosomes, and leveraged these assemblies to scaffold and assemble a further 103 trypanosome maxicircle gene coding regions from published short-read data. While synteny was largely conserved, there were repeated, independent losses of Complex I genes. Comparison of pre-edited and non-edited genes revealed the impact of RNA editing on nucleotide composition, with non-edited genes approaching the limits of GC loss. African tsetse-transmitted trypanosomes showed high levels of RNA editing compared to other trypanosomes. The gene coding regions of maxicircle mitochondrial DNAs were used to construct time-resolved phylogenetic trees, revealing deep divergence events among isolates of the pathogens Trypanosoma brucei and T. congolense.

Conclusions

Our data represents a new resource for experimental and evolutionary analyses of trypanosome phylogeny, molecular evolution and function. Molecular clock analyses yielded a timescale for trypanosome evolution congruent with major biogeographical events in Africa and revealed the recent emergence of Trypanosoma brucei gambiense and T. equiperdum, major human and animal pathogens.

Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

Reducing inequity in primary care clinics treating low socioeconomic Jewish and Arab populations in Israel

Background

An organization-wide inequity-reduction quality improvement (QI) initiative was implemented in primary care clinics serving disadvantaged Arab and Jewish populations. Using the Chronic Care Model (CCM), this study investigated the types of interventions associated with success in inequity reduction.

Methods

Semi-structured interviews were conducted with 80 staff members from 26 target clinics, and information about intervention types was coded by CCM and clinical domains (e.g. diabetes, hypertension and lipid control; performance of mammography tests). Relationships between type and number of interventions implemented and inequity reduction were assessed.

Results

Target clinics implemented 454 different interventions, on average 17.5 interventions per clinic. Interventions focused on Decision support and Community linkages were positively correlated with improvement in the composite quality score (P < 0.05). Conversely, focusing on a specific clinical domain was not correlated with a higher quality score.

Conclusions

Focusing on training team members in selected QI topics and/or tailoring interventions to meet community needs was key to the interventions' success. Such findings, especially in light of the lack of association between QI and a focus on a specific clinical domain, support other calls for adopting a systems approach to achieving wide-scale inequity reduction.

Multidimensional Treatment Foster Care for Adolescents in English care: randomised trial and observational cohort evaluation

BACKGROUND

Children in care often have poor outcomes. There is a lack of evaluative research into intervention options.

AIMS

To examine the efficacy of Multidimensional Treatment Foster Care for Adolescents (MTFC-A) compared with usual care for young people at risk in foster care in England.

METHOD

A two-arm single (assessor) blinded randomised controlled trial (RCT) embedded within an observational quasi-experimental case-control study involving 219 young people aged 11-16 years (trial registration: ISRCTN 68038570). The primary outcome was the Child Global Assessment Scale (CGAS). Secondary outcomes were ratings of educational attendance, achievement and rate of offending.

RESULTS

The MTFC-A group showed a non-significant improvement in CGAS outcome in both the randomised cohort (n = 34, adjusted mean difference 1.3, 95% CI -7.1 to 9.7, P = 0.75) and in the trimmed observational cohort (n = 185, adjusted mean difference 0.95, 95% CI -2.38 to 4.29, P = 0.57). No significant effects were seen in secondary outcomes. There was a possible differential effect of the intervention according to antisocial behaviour.

CONCLUSIONS

There was no evidence that the use of MTFC-A resulted in better outcomes than usual care. The intervention may be more beneficial for young people with antisocial behaviour but less beneficial than usual treatment for those without.

Abstract PD3-2: Accurate and robust prediction of clinical response to aromatase inhibitors by two weeks of neoadjuvant breast cancer treatment

Background: Aromatase inhibitors (AIs) have an established role in the treatment of estrogen receptor alpha positive (ER+) post-menopausal breast cancer. Response rates are 50-70% in the neoadjuvant setting and lower in advanced disease. There is a need to identify biomarkers to predict response that outperform those currently available, to be able to offer more stratified treatments and improved patient care.

Methods: Pre- and on-treatment (at 14 days and 3-months) biopsies were obtained from 89 post-menopausal women with ER+ breast cancer receiving 3 months of neoadjuvant Letrozole. Illumina Beadarray gene expression data (n = 34) were combined with Affymetrix GeneChip data (n = 55) and cross-platform integration approaches developed as part of this study were implemented to combine data. Dynamic clinical response was assessed for each patient using periodic 3D ultrasound measurements performed during treatment. A gene classifier was developed from pre and 14 day gene array expression data to predict response. An independent series from the Royal Marsden was used to validate the classifier.

Results: Response to endocrine therapy in the neoadjuvant setting based on the expression of 4 genes has been developed. The classifier comprises baseline expression of an immune signalling gene and an apoptosis related gene, together with 14 day expression of two proliferation genes. Early on-treatment gene changes in combination with pre-treatment gene expression significantly improve predictive power compared to pre-treatment gene expression alone. The classifier had a 96% accuracy in a training dataset (n = 73) and 91% accuracy in an independent validation dataset (n = 44) dataset.

Table 1 AccuracySensitivitySpecificityPPVNPVAUC (ROC)Training0.960.890.980.890.960.96Validation0.910.80.970.920.9NASensitivity and specificity of model in training and validation datasets

Expression of the pre-treatment immune signalling gene alone predicted for response with 85% and 82% accuracy in training and validation datasets respectively. Higher pre-treatment levels of this gene were associated with a significantly better 1 year progression free survival (PFS) (P = 0.0001). In a larger series of patients treated with neoadjuvant Letrozole (n = 129) higher expression of this gene alone was associated with a significantly improved 10 year RFS (p = 0.0359). In a separate tamoxifen treated cohort (n = 212) higher expression of this gene at diagnosis was associated with a significantly improved 5 year (p = 0.0015) and 10 year (p = 0.04) recurrence free survival (RFS).

Conclusion:

• A 4 gene classifier has been developed and validated to predict response to neoadjuvant Letrozole.

• One of the genes identified is a significant predictor in independent data sets of long term RFS in endocrine treated patients.

• This new classifier has the potential to predict accurately the benefit of endocrine therapy and has huge potential clinical value.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD3-2.

Prior MDMA exposure inhibits learning and produces both tolerance and sensitization in the radial-arm maze

Recent research using the partially-baited radial arm maze with rats has shown that acute or single-session high-dose exposure to +/-3,4-methylenedioxymethaphemtamine (MDMA) impairs reference memory processes more so than working memory processes. The current study examined the effect that an initial binge exposure of MDMA had on the ability to learn this task and whether such exposure produced tolerance or sensitization to subsequent low dose acute MDMA exposure. Following either an initial binge dose (4×10mg/kg) of MDMA or saline, rats received regular weekly injections of either MDMA (4.0mg/kg) or saline during task acquisition training. Although eventually able to acquire the task at a level comparable to controls, initial binge MDMA exposure significantly impaired task acquisition. Binge-treated rats displayed evidence of a tolerance effect to subsequent acute injections of MDMA; although with continued training this tolerance effect was reduced. However, initial binge treatment also produced a sensitized response to subsequent acute MDMA exposure that manifested as a prolonged period of impairment up to 24h following administration. Consistent with the effects seen following other regimes of exposure to MDMA, the pattern of errors made was best described as an impairment to reference memory processes as opposed to working memory processes.

Abstract P6-04-09: Lack of response to aromatase inhibitors involves distinct mechanisms

Background: Estrogen is a key hormone involved in cancer cell development. It forms a complex with estrogen receptor alpha (ER) which binds to estrogen response elements (EREs) in the promoter regions of genes under its transcriptional control. Letrozole inhibits local production of estrogen. Despite the prevalent use of such drugs little is known about their effect at molecular and transcriptomic level. A better understanding of the molecular mechanisms underlying why approximately 75% of ER rich cancers respond might help to elucidate the mechanisms characterising a lack of response in some patients.

Methods: A new gene expression dataset was generated from sequential core biopsy/theatre samples (before treatment, 10–14 days on treatment and at surgery) taken from ER+ patients undergoing neo-adjuvant letrozole treatment. Clinical response to treatment was assessed by changes in tumour volume based on 3D ultrasound (performed by a single operator).

Results: On letrozole the majority of ER+ tumours respond with dramatic early transcriptomic changes. A significant reduction in proliferation is seen through down-regulation of key cell cycle control genes such as CyclinD1, CyclinA, CyclinB1, CyclinB2 and CDK2, and genes involved with the initiation phase of DNA replication such as the MCM complex. Several of these (including CyclinD1, CyclinB2 and MCM2) have been shown to contain candidate ERE sequences in their promoter region and therefore down-regulation of these would be concordant with deprivation of estrogen. There is also a significant up-regulation of genes including collagens, lamanins, integrins and others involved with intra-cellular adhesion and extra-cellular matrix (ECM) remodelling. Preliminary analysis suggests the involvement of a local immune response as a potential mechanism for tumour cell death, as genes involved with antigen presentation, leukocyte trans-endothelial mediation, natural killer cell mediated cytotoxicity and T-cell mediated cell death are significantly up-regulated within the clinically responding group.

Two distinct subsets were seen in non-responders. The first subgroup shows a ‘classical non-response profile’ with very little change in expression of genes involved with cell cycle, ECM remodelling, cellular adhesion and antigen presentation between baseline and 14-days of treatment. The second subgroup have a gene expression profile similar to the responding group with a down-regulation of cell cycle and up-regulation of genes involved with ECM remodelling, cellular adhesion and antigen presentation. Whether these are true non-responders is not clear.

Conclusion: Approximately half of clinically non-responding patients have molecular profiles similar to responding patients whilst the other half have a distinct pattern of expression with significantly less change in genes associated with cell cycle control, ECM remodelling, intra-cellular adhesion and antigen presentation. On-going work will elucidate long term outcomes in these two groups.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-09.

Abstract P3-06-23: Predicting response to neoadjuvant letrozole

Background: Approximately 75% of older postmenopausal patients with large operable or locally advanced oestrogen receptor positive breast cancer respond to treatment with neoadjuvant letrozole. Prediction of response is required as approximately 25% fail to respond. The aim of this study was to design a response predicting classifier with two data sets, one published previously [1] and secondly a new dataset.

Methods: Patients were treated with Letrozole (Femara, 2.5 mg daily) and tissues were collected before treatment, 2 or 3 weeks on treatment, and between 3 and 5 months on treatment. Response was based on a 3D ultrasound, with response being classified as a 50% reduction in tumour volume at 3 months. To ensure biological relevance of the response groups we also separated patients into Quick Stable Responders (QSR) and Long-Term Non-responders (LNR), as summarised in Table 1.

Abstract PD10-02: Metabolic syndrome and recurrence within the 21-gene recurrence score assay risk categories in lymph node negative breast cancer

Background: The incidence of the metabolic syndrome (MS) has been increasing in the United States and elsewhere. The interaction of MS with breast cancer (BC) incidence, tumor biology and outcomes are under study. We hypothesized that the presence of MS would predict BC recurrence to a variable degree across the diverse BC biology as defined by the risk categories of the 21-gene recurrence score (RS) assay.

Patients and Methods: We studied consecutive patients (pts) with newly diagnosed, estrogen receptor (ER) positive, lymph node (LN) negative BC treated in our institution between 2006–2011 who had a 21-gene RS assay done on their tumors. All pts were treated with standard systemic and local therapy. The electronic medical record was queried for key diagnoses including MS and its constituent parts. The WHO definition was used to categorize pts as having MS defined as diabetes mellitus (DM) or glucose intolerance, plus at least 2 of the following: hypertension (HTN), dyslipidemia (HL), central obesity and microalbuminemia. Tumor characteristics including Ki67 index, grade, tumor size, HER2/neu status; and pt characteristics including age, race, menopausal status, body mass index were recorded. The association of MS and the tumor and patient characteristics with the RS tertiles of low, intermediate and high risk was analyzed.

Results: We identified 332 pts, median age 62 years, of whom 88 (27%) had MS. There was no significant association between the MS and any of the patient or tumor variables including the 21-gene RS assay, except for race (p = 0.004). Eleven of 21 (52%) African-American women had MS, 68 of 284 (24%) Caucasian women had MS, and 9 of 21 (43%) others including Hispanic and Asian women had MS. However, there was a significant association between recurrence and MS (p = 0.0002) independent of other factors. Of the 21 pts who recurred, 13 (61.9%) had MS. There was an association of recurrence and MS within RS tertiles. For pts with low risk scores, 7/44 (15.9%) with MS vs. 1/126 (0.79%) without MS had recurrence (p = 0.0003). For pts with intermediate risk scores, 5/30 (16.67%) with MS vs. 4/83 (4.82%) without MS had recurrence (p = 0.05). For patients with high risk scores, 1/9 (11.11%) with MS vs. 2/15 (13.33%) without MS had recurrence (p = 1).

Conclusion: MS is an independent risk factor for BC recurrence among women with LN negative, ER positive BC treated with standard adjuvant therapy. There is a striking impact of MS on recurrence in pts with tumor biologies defined by low (and to a lesser degree) intermediate risk 21-gene RS assay scores. However, there is no difference in recurrence risk by MS among those pts with high RS. This implies that interventions directed at modifying MS in newly diagnosed pts with early BC may potentially favorably impact survival in those with specific tumor biologies as defined by multigene assays. Thus, long-term prospective studies should be conducted to further evaluate both the short and long term effects of MS on BC outcomes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-02.

Defining the molecular response to trastuzumab, pertuzumab and combination therapy in ovarian cancer

BACKGROUND

Trastuzumab and pertuzumab target the Human Epidermal growth factor Receptor 2 (HER2). Combination therapy has been shown to provide enhanced antitumour activity; however, the downstream signalling to explain how these drugs mediate their response is not clearly understood.

METHODS

Transcriptome profiling was performed after 4 days of trastuzumab, pertuzumab and combination treatment in human ovarian cancer in vivo. Signalling pathways identified were validated and investigated in primary ovarian xenografts at the protein level and across a timeseries.

RESULTS

A greater number and variety of genes were differentially expressed by the combination of antibody therapies compared with either treatment alone. Protein levels of cyclin-dependent kinase inhibitors p21 and p27 were increased in response to both agents and further by the combination; pERK signalling was inhibited by all treatments; but only pertuzumab inhibited pAkt signalling. The expression of proliferation, apoptosis, cell division and cell-cycle markers was distinct in a panel of primary ovarian cancer xenografts, suggesting the heterogeneity of response in ovarian cancer and a need to establish predictive biomarkers.

CONCLUSION

This first comprehensive study of the molecular response to trastuzumab, pertuzumab and combined therapy in vivo highlights both common and distinct downstream effects to agents used alone or in combination, suggesting that complementary pathways may be involved.

Successful Treatment of Peripartum Massive Pulmonary Embolism with Extracorporeal Membrane Oxygenation and Catheter-Directed Pulmonary Thrombolytic Therapy

Chronic thromboembolic pulmonary hypertension during pregnancy is uncommon but is associated with maternal mortality in excess of 35%. We report a case of decompensated thromboembolic pulmonary hypertension requiring emergency caesarean section and postpartum treatment with extracorporeal membrane oxygenation and thrombolytic therapy with urokinase. The use of extracorporeal membrane oxygenation, catheter-directed pulmonary thrombolytic therapy and other pulmonary vasodilators for management of this life-threatening disease is discussed.

Detection of Pseudomonas syringae pv actinidiae in kiwifruit pollen samples

Presence of Pseudomonas syringae pv actinidiae (Psa) the causal agent of bacterial canker of kiwifruit in pollen samples collected from infected and non infected orchards in Italy and in New Zealand was determined by polymerase chain reaction (PCR) and by direct bacterial isolation Psa was isolated only from pollen samples collected in Italy including pollen collected from two uninfected orchards which the following year showed signs of infection Psa was also detected in pollen collected from male and female vines in an Italian infected orchard Pollen samples from Italy but not from New Zealand were collected with a vacuum device Psa could not be isolated from any of the 25 New Zealand pollen samples analysed This is the first report of Psa being associated with pollen There is currently no evidence that artificial pollination leads to increased infection or that pollen has been responsible for the introduction of Psa in a previously Psafree area

Abstract P2-09-12: Phosphoproteomic Pathway Profiling of Breast Cancers for Biomarker and Target Discovery for Personalized Therapy

Introduction: The control and activation of signaling pathways has been shown to influence response to targeted therapy (PTEN and PI3K for trastuzumab, KRAS and MAPK for cetuximab). Single tissue biomarkers (eg HER2-receptor status) are often poor surrogates for the activation state of downstream pathways such as MAPK and PI3K. We have used phosphoproteomic profiling in order to reclassify breast tumors for therapeutic response prediction.

Methods: Eleven cell lines were profiled using phosphoproteome arrays (250 targets) and reclassified using unsupervised clustering. Sensitivity to therapy predicted by pathway activation status was correlated with sensitivity to therapies in vitro measured by the AlamarBlue cell viability assay. Target specificity was assayed using in-cell western blotting. Phosphoprotein clusters were validated in 107 breast tumors by reverse phase protein arrays (RPPA), and the expression of targets validated in independent cohorts of cancers by quantitative immunofluorescence (AQUA) on tissue microarrays.

Results: Phosphoproteomic profiling revealed 3 main clusters of breast tumors with overlap with existing molecular phenotypes (luminal, basal, and mixed) and different profiles of pathway activation (Cluster A: anti-apoptotic, Cluster B: growth factor-dependent, Cluster C: cell cycle-dependent). Good to excellent correlations between pathway activation and in vitro sensitivity to targeted therapies were shown for several pathways and individual molecules within pathways, including components of NFkB, STAT, and cell cycle. These biomarkers were shown to be present in clinical cohorts by RPPA and AQUA, and related to molecular phenotype. Conclusions: Phosphoproteomic profiling can be used to reclassify tumors in order to make a priori predictions about therapeutic targeting. These clusters exist in real clinical specimens and are therefore also promising biomarkers for targeted therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-12.

Abstract P5-05-06: The Role of Sprouty 2 in HER2 Signaling in Breast Cancer; Decreased Expression Is Associated with Poor Outcome Including in Trastuzumab-Treated Patients

Purpose: Resistance to trastuzumab is a frequent clinical problem, in part due to the overriding activation state of the MAPK/PI3K signaling pathways. Sprouty-family proteins are negative regulators of MAPK/PI3K signaling, but their role in HER2 signaling and resistance to therapy is unknown.

Experimental design: The association of Sprouty 2 gene expression with grade, HER2-status, and survival was investigated in a meta-analysis of 1107 breast tumors from six published microarray studies. Sprouty regulation in response to HER2/HER3 signaling was studied using qRT-PCR. Changes in expression of Spry2 and feedback inhibition on trastuzumab-resistance were studied using full-length/dominant-negative transfection or chemical inhibition in SKBr3 and BT474 cell lines in cell viability assays. Finally, expression of Spry2 was measured in a cohort of 122 patients treated with trastuzumab by quantitative fluorescence microscopy (AQUA).

Results: Low Spry2 gene expression was associated with high HER2 protein expression. Spry2 was regulated through HER2/HER3 signaling as a delayed early gene, an effect reversed by treatment with the dimerization inhibitor pertuzumab. Overexpression of Spry2 in the SKBr3 trastuzumab-resistant cell line resulted in synergistic inhibition of cell viability with trastuzumab. Restitution of feedback inhibition with the PI3K-inhibitor LY294002 had a similar effect. Low Spry2 expression was associated with increased risk of death (HR = 2.28, 95% CI 1.22 - 4.26; p=0.008) in trastuzumab-treated patients, including in multivariate analysis (Cox regression analysis, p=0.002).

Conclusions: These results suggest that combinations of negative regulators of growth factor signaling may be an effective therapeutic strategy in breast cancers with deficient feedback inhibition.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-05-06.

Differential effects of MDMA and scopolamine on working versus reference memory in the radial arm maze task

Previous research has suggested that the disruption to memory-task performance seen following acute exposure to 3,4-methylenedioxymethaphemtamine (MDMA) with rats might best be characterized as reference memory impairment rather than a working memory impairment. The current study specifically compared the effects of MDMA and scopolamine on measures of working versus reference memory in an eight-arm radial maze task. It was predicted that scopolamine would produce a greater impairment with respect to the working memory component of the task, whereas MDMA would produce a greater impairment to reference memory. On each trial rats were allowed to make a total of four arm visits in order to collect the reinforcers located at the end of different arms in the maze. Working memory errors were indicated by re-visiting an already visited arm during a trial, whereas visiting an arm that was never baited on any trial indicated a reference memory error. Using a within subjects design, rats were exposed to a range of doses of scopolamine and MDMA administered acutely. An interaction between drug type and memory error type was found. Specifically, scopolamine produced more working memory errors than reference memory errors, while MDMA produced the opposite pattern of significantly more reference memory errors compared to working memory error. This finding supported the hypothesis that MDMA disrupts reference memory processes in terms of an impairment in the strategies or rules used for solving memory tasks.

Faecal indicator organism concentrations and catchment export coefficients in the UK

Characterisation of faecal indicator organism (FIO) concentrations and export coefficients for catchments with particular combinations of land use and under specific climatic regimes is critical in developing models to predict daily loads and apportion sources of the microbial parameters used to regulate water quality. Accordingly, this paper presents a synthesis of FIO concentration and export coefficient data for the summer bathing season, with some comparative winter data, for 205 river/stream sampling points widely distributed across mainland UK. In terms of both geometric mean (GM) FIO concentrations and export coefficients (expressed as cfu km(-2) h(-1)), the results reveal (1) statistically significant elevations at high flow compared with base flow, with concentrations typically increasing by more than an order of magnitude and export coefficients by about two orders; (2) significantly higher values in summer than in winter under high-flow conditions; and (3) extremely wide variability between the catchments (e.g. four orders of magnitude range for GM faecal coliform concentrations), which closely reflects land use-with urban areas and improved pastures identified as key FIO sources. Generally, these two most polluting land uses are concentrated in lowland areas where runoff (m3 km(-2) h(-1)) is low compared with upland areas, which in the UK are dominated by rough grazing and forestry. Consequently, contrasts in export coefficients between land use types are less than for FIO concentrations. The GMs reported for most land use categories are based on 13 sites and exhibit quite narrow confidence intervals. They may therefore be applied with some confidence to other catchments in the UK and similar geographical regions elsewhere. Examples are presented to illustrate how the results can be used to estimate daily summer base- and high-flow FIO loads for catchments with different land use types, and to assess the likely effectiveness of certain strategies for reducing FIO pollutant loadings in areas with extensive areas of lowland improved pasture.

Reducing fluxes of faecal indicator compliance parameters to bathing waters from diffuse agricultural sources: the Brighouse Bay study, Scotland

The European Water Framework Directive requires the integrated management of point and diffuse pollution to achieve 'good' water quality in 'protected areas'. These include bathing waters, which are regulated using faecal indicator organisms as compliance parameters. Thus, for the first time, European regulators are faced with the control of faecal indicator fluxes from agricultural sources where these impact on bathing water compliance locations. Concurrently, reforms to the European Union (EU) Common Agricultural Policy offer scope for supporting on-farm measures producing environmental benefits through the new 'single farm payments' and the concept of 'cross-compliance'. This paper reports the first UK study involving remedial measures, principally stream bank fencing, designed to reduce faecal indicator fluxes at the catchment scale. Considerable reduction in faecal indicator flux was observed, but this was insufficient to ensure bathing water compliance with either Directive 76/160/EEC standards or new health-evidence-based criteria proposed by WHO and the European Commission.

CT colonography: interpretative performance in a non-academic environment

AIM

To investigate interpretative accuracy and reporting time for radiologists performing computed tomography (CT) colonography in day-to-day non-academic clinical practice.

MATERIALS AND METHODS

Thirteen radiologists from seven centres, who were reporting CT colonography in non-academic daily clinical practice, interpreted a dataset of 15 colonoscopically validated cases in a controlled environment. Ten cases had either a cancer or polyp >10mm; one case had a medium polyp and four were normal. Correct case categorization and interpretation times were compared using analysis of variance to aggregated results obtained from both experienced observers and observers recently trained using 50 cases, working in an academic environment. The effect of experience was determined using Spearman's rank correlation.

RESULTS

Individual accuracy was highly variable, range 53% (95% CI 27-79%) to 93% (95% CI 68-100%). Mean accuracy overall was significantly inferior to experienced radiologists (mean 75 versus 88%, p=0.04) but not significantly different from recently trained radiologists (p=0.48). Interpretation time was not significantly different to experienced readers (mean 12.4 min versus 11.7, p=0.74), but shorter than recently trained radiologists (p=0.05). There was a significant, positive, linear correlation between prior experience and accuracy (p<0.001) with no plateau.

CONCLUSION

Accuracy for sub-specialist radiologists working in a non-academic environment is, on average, equivalent to radiologists trained using 50 cases. However, there is wide variability in individual performance, which generally falls short of the average performance suggested by meta-analysis of published data. Experience improves accuracy, but alone is insufficient to determine competence.

Role of p53 codon 72 polymorphism in recurrent pregnancy loss

Recurrent pregnancy loss (RPL) has been associated with low expression of apoptosis-and angiogenesis-related genes. The p53 tumour suppressor gene has been shown to induce apoptosis and angiogenesis. Recently, a low increased frequency of a p53 codon 72 polymorphism has been reported among women experiencing RPL. This study investigated the prevalence of p53 codon 72 polymorphism among women with a history of RPL, to determine whether this polymorphism may serve as a risk factor for miscarriage. Buccal swabs were obtained from 205 women with a history of two or more consecutive spontaneous abortions and 25 women with at least two live births and not more than one elective abortion. DNA was extracted from the buccal swabs and PCR amplification of p53 arginine(Arg)72 and proline(Pro)72 variants was performed. The frequency of homozygous Arg and Pro or heterozygous Arg/Pro genotypes among RPL patients and controls were not significantly different. No significant differences in allelic frequencies of p53 were observed. In addition, the allelic frequencies between controls and those previously reported were the same. It is concluded that p53 codon 72 polymorphisms do not serve as a susceptibility factor affecting the chances of miscarriage in an unselected population.

Effects of repeated low-dose UVB irradiation on the hyphal growth of Candida albicans

Ultraviolet B light (UVB) can have negative phototropic effects on fungi. Candida albicans is often found on human skin exposed to UVB. Therefore, it is of medical interest to know whether a negative phototropic response to UVB irradiation can support an invasive growth of this potentially dangerous agent. In our study we investigated how repeated irradiation with low doses of UVB can influence the hyphal growth of C. albicans. Six randomly chosen strains of C. albicans were tested. Formation of hyphae was induced and maintained within transparent agar plates. The fungi were exposed to UVB three times daily for 7 days from either the observe or the reverse side during incubation. The wavelength spectrum was in the range of 310-315 nm, single doses were between 0.0018 and 0.432 J cm(-2). After 7 days the morphology and growth direction of C. albicans cells were determined microscopically. All six strains showed a common and dose-dependent response to UVB irradiation: the progression of hyphal growth was inhibited, no phototropic effects were seen and as a new finding an increased formation of blastospores was observed. We conclude that an irradiation of human skin colonized by C. albicans with doses of UVB that can occur under natural or artificial conditions is unlikely to trigger skin invasion by C. albicans.

p53 tumour suppressor gene polymorphism is associated with recurrent implantation failure

Implantation failure is the most frequent cause of lack of pregnancy after IVF and embryo transfer. Successful implantation requires trophoblastic growth into the endometrium to stimulate its own blood supply. The p53 tumour suppressor gene has been shown to regulate cell growth and induce angiogenesis. Therefore, the prevalence of p53 codon 72 polymorphism was investigated among women with a history of recurrent implantation failure to determine whether this polymorphism may serve as a risk factor for implantation failure. DNA was extracted from the buccal swabs obtained from 70 women experiencing implantation failure and polymerase chain reaction amplification of p53 arginine (Arg) 72 and proline (Pro) 72 variants were performed. The frequency of homozygous Arg and Pro or heterozygous Arg/Pro genotypes was compared with frequencies among 205 women experiencing recurrent pregnancy loss and 20 control women. The frequency of Pro72 was significantly higher (P=0.003) among women experiencing recurrent implantation failure compared with women experiencing recurrent miscarriage and with control women. It is concluded that p53 codon 72 polymorphisms may serve as a susceptibility factor affecting the chances of recurrent implantation after IVF or embryo transfer.