The role of national and international veterinary laboratories

In the field of diagnostic test validation, World Organisation for Animal Health (OIE) Reference Laboratories (RLs) have a pivotal role and provide the international community with impartial advice and support in the selection, development and validation of diagnostic tests, which can be applied to the specialist diseases for which they are designated. National RLs provide an invaluable function in supporting the introduction, ongoing validation and application of validated diagnostic tests in line with international standards. Experienced staff with extensive knowledge of such systems and access to specialist facilities for conducting work are available to monitor changes or advancements in technology. They consider their relevance and value to evolving diagnostic test requirements. Reference Laboratories often have a broad mandate of activity linking research or development programmes and surveillance activities to benefit the continual assessment and, if necessary, improvement of diagnostic tools. Reference Laboratories maintain or have access to unique biological archives (known positive and negative sample populations) and produce international reference standards, both of which are vital in establishing the necessary and detailed validation of any diagnostic test. Reference Laboratories act either singularly or in collaborative partnerships with other RLs or science institutes, but also, when required, and with impartiality, with the commercial sector, to ensure new tests are validated according to OIE standards. They promote and apply formal programmes of quality assurance (including proficiency testing programmes) for newly validated tests, ensuring ongoing monitoring and compliance with standards, or as required set out any limitations or uncertainties. Reference Laboratories publish information on test validation in the scientific literature and on relevant websites, as well as disseminating information at workshops and international conferences. Furthermore, they can offer training in the processes and systems underpinning test validation.

HER-2 status of circulating tumor cells in a metastatic breast cancer cohort: A comparative study on characterization techniques

Background

Personalized targeted treatment in metastatic breast cancer relies on accurate assessment of molecular aberrations, e.g. overexpression of Human Epidermal growth factor Receptor 2 (HER-2). Molecular interrogation of circulating tumor cells (CTCs) can provide an attractive alternative for real-time biomarker assessment. However, implementation of CellSearch-based HER-2 analysis has been limited. Immunofluorescent (IF) image interpretation is crucial, as different HER-2 categories have been described. Major questions in CTC research are how these IF categories reflect gene expression and amplification, and if we should consider ‘medium’ HER-2 expressing CTCs for patient selection.

Methods

Tumor cells from spiked cell lines (n = 8) and CTCs (n = 116 samples) of 85 metastatic breast cancer patients were enriched using CellSearch. Comparative analysis of HER-2 expression by IF imaging (ACCEPT, DEPArray, and visual scoring) with qRT-PCR and HER-2/neu FISH was performed.

Results

Automated IF HER-2-profiling by DEPArray and ACCEPT delivered comparable results. There was a 98% agreement between 17 trained observers (visual scoring) and ACCEPT considering HER-2^neg and HER-2^high expressing CTCs. However, 89% of HER-2^med expressing CTCs by ACCEPT were scored negative by observers. HER-2^high expressing tumor cells demonstrated HER-2/neu gene amplification, whereas HER-2^neg and HER-2^med expressing tumor cells and CTCs by ACCEPT were copy-number neutral. All patients with HER-2-positive archival tumors had ≥1 HER-2^high expressing CTCs, while 80% of HER-2-negative patients did not. High relative gene expression of HER-2 measured on enriched CTC lysates correlated with having ≥1 HER-2^high expressing CTCs.

Conclusion

Automated images analysis has enormous potential for clinical implementation. HER-2 characterization and clinical trial design should be focused on HER-2^high expressing CTCs.

TP53 Outperforms Other Androgen Receptor Biomarkers to Predict Abiraterone or Enzalutamide Outcome in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

To infer the prognostic value of simultaneous androgen receptor (AR) and TP53 profiling in liquid biopsies from patients with metastatic castration-resistant prostate cancer (mCRPC) starting a new line of AR signaling inhibitors (ARSi).Experimental Design: Between March 2014 and April 2017, we recruited patients with mCRPC (n = 168) prior to ARSi in a cohort study encompassing 10 European centers. Blood samples were collected for comprehensive profiling of CellSearch-enriched circulating tumor cells (CTC) and circulating tumor DNA (ctDNA). Targeted CTC RNA sequencing (RNA-seq) allowed the detection of eight AR splice variants (ARV). Low-pass whole-genome and targeted gene-body sequencing of AR and TP53 was applied to identify amplifications, loss of heterozygosity, mutations, and structural rearrangements in ctDNA. Clinical or radiologic progression-free survival (PFS) was estimated by Kaplan-Meier analysis, and independent associations were determined using multivariable Cox regression models.

RESULTS

Overall, no single AR perturbation remained associated with adverse prognosis after multivariable analysis. Instead, tumor burden estimates (CTC counts, ctDNA fraction, and visceral metastases) were significantly associated with PFS. TP53 inactivation harbored independent prognostic value [HR 1.88; 95% confidence interval (CI), 1.18-3.00; P = 0.008], and outperformed ARV expression and detection of genomic AR alterations. Using Cox coefficient analysis of clinical parameters and TP53 status, we identified three prognostic groups with differing PFS estimates (median, 14.7 vs. 7.51 vs. 2.62 months; P < 0.0001), which was validated in an independent mCRPC cohort (n = 202) starting first-line ARSi (median, 14.3 vs. 6.39 vs. 2.23 months; P < 0.0001).

CONCLUSIONS

In an all-comer cohort, tumor burden estimates and TP53 outperform any AR perturbation to infer prognosis.See related commentary by Rebello et al., p. 1699.

Associations between endocrine disrupting chemicals and equine metabolic syndrome phenotypes

Equine Metabolic Syndrome (EMS) is characterized by abnormalities in insulin regulation, increased adiposity and laminitis, and has several similarities to human metabolic syndrome. A large amount of environmental variability in the EMS phenotype is not explained by commonly measured factors (diet, exercise, and season), suggesting that other environmental factors play a role in EMS development. Endocrine disrupting chemicals (EDCs) are associated with metabolic syndrome and other endocrine abnormalities in humans. This led us to hypothesize that EDCs are detectable in horse plasma and play a role in the pathophysiology of EMS. EDCs acting through the aryl hydrocarbon and estrogen receptors, were measured in plasma of 301 horses from 32 farms. The median (range) TEQ (2,3,7,8-TCDD equivalent) and EEQ (17β-estradiol equivalent) were 19.29 pg/g (0.59-536.36) and 10.50 pg/ml (4.35-15000.00), respectively. TEQ was negatively associated with plasma fat extracted and batch analyzed. EEQ was positively associated with pregnancy and batch analyzed, and negatively associated with being male and superfund score ≤100 miles of the farm. Of particular interest, serum glucose and insulin, glucose and insulin post oral sugar challenge, and leptin concentrations were associated with EEQ, and serum triglyceride concentration was associated with TEQ. Overall, we demonstrated that EDCs are present in the plasma of horses and may explain some of the environmental variability in measured EMS phenotypes. This is the first example of EDCs being associated with clinical disease phenotype components in domestic animals.

On the Fibrinolytic System in Aged Rats, and Its Reactivity to Endotoxin and Cytokines

Aged rats are more susceptible to endotoxin-induced effects, including microthrombosis and platelet aggregation, than are young rats. To investigate whether changes in the fibrinolytic system might be involved, we investigated the fibrinolytic activity in plasma euglobulin fractions and tissues (lung and heart) of young (6-months old) and aged (24-months old) rats under baseline conditions and after challenge with endotoxin. Aged rats had lower plasma levels of tissue-type plasminogen activator (t-PA) and of urokinase-type PA (u-PA) activity. PA inhibitor (PAI) activity was higher in the plasma of aged rats, as was t-PA activity in lung and heart.

Rats were treated with either a low dose (1 μg/kg) or a high dose (10 mg/kg) of endotoxin. Both treatments induced a transient phase of increased blood fibrinolytic activity, as evidenced by higher levels of tissue-type plasminogen activator (t-PA) activity and decreased levels of PA inhibitor (PAI) activity. Over time, the fibrinolytic activity decreased, probably due to increased levels of PA inhibitor.

Both the early increase in t-PA activity, and the subsequent increase in PAI activity, were more pronounced in the aged rats, as compared with the younger rats, after the high dose of endotoxin. The aged rats also responded to an injection of interleukin-1β or tumor necrosis factor-α with a larger increase of PAI activity than did the younger rats.

Together the data suggest that, compared to young rats, aged rats have a decreased base-line plasma fibrinolytic activity, while their fibrinolytic system is more responsive to challenge by endotoxin and cytokines.

Circulating tumor cells and survival in abiraterone- and enzalutamide-treated patients with castration-resistant prostate cancer

BACKGROUND

The outcome to treatment administered to patients with metastatic castration-resistant prostate cancer (mCRPC) greatly differs between individuals, underlining the need for biomarkers guiding treatment decision making.

OBJECTIVE

To investigate the prognostic value of circulating tumor cell (CTC) enumeration and dynamics, in the context of second-line endocrine therapies (ie, abiraterone acetate or enzalutamide), irrespective of prior systemic therapies.

DESIGN, SETTINGS, AND PARTICIPANTS

In a prospective, multicentre study blood samples for CTC enumeration were collected from patients with mCRPC at baseline (n = 174). In patients who responded for minimally 10-12 weeks a follow-up sample was collected.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

For baseline analysis, patients were stratified in <5 or ≥5 CTCs/7.5 mL, whereas for the analysis of CTC dynamics at 10-12 weeks, in patients with stable, increasing or decreasing CTC counts. Progression-free survival (PFS), overall survival (OS), and PSA changes at 10-12 weeks were compared between groups.

RESULTS

Patients demonstrating increasing CTCs on therapy had a shorter median PFS (4.03 vs 12.98 vs 13.67 months, HR 3.6, 95%CI 1.9-6.8; P < 0.0001) and OS (11.2 months vs not reached, HR 9.5, 95%CI 3.7-24; P < 0.0001), compared to patients with decreasing or stable CTCs. Multivariable Cox regression showed that prior chemotherapy (HR 4.1, 95%CI 1.9-8.9; P = 0.0003), a high baseline CTC count (HR 1.5, 95%CI 1.2-1.9; P = 0.002) and increasing CTCs at follow-up (HR 3.3, 95%CI 1.4-7.6; P = 0.005) were independent predictors of worse PFS. Previous chemotherapy (HR 7, 95%CI 1.9-25; P = 0.003), high baseline CTC counts (HR 2.2, 95%CI 1.4-3.7; P = 0.002) and increasing CTCs during therapy (HR 4.6, 95%CI 1.4-15; P = 0.01) were independently associated with shorter OS. ≥30% and ≥50% PSA responses less frequently occurred in patients with CTC inclines at 10-12 weeks on therapy (χ² test: P < 0.01).

CONCLUSIONS

CTC dynamics during therapy are associated with PSA response and provide independent clinical prognostication over PSA declines. Hence the study demonstrates the pharmacodynamic properties of CTCs.

Evaluation and consequences of heterogeneity in the circulating tumor cell compartment

A growing understanding of the molecular biology of cancer and the identification of specific aberrations driving cancer evolution have led to the development of various targeted agents. Therapeutic decisions concerning these drugs are often guided by single biopsies of the primary tumor. Yet, it is well known that tumors can exhibit significant heterogeneity and change over time as a result of selective pressure. Circulating tumor cells (CTCs) are shed from various tumor sites and are thought to represent the molecular landscape of a patient's overall tumor burden. Moreover, a minimal-invasive liquid biopsy facilitates monitoring of clonal evolution during therapy pressure and disease progression in real-time. While more information becomes available regarding heterogeneity among CTCs, comparison between these studies is needed. In this review, we focus on the genomic and transcriptional heterogeneity found in the CTC compartment, and its significance for clinical decision making.

Light therapy: is it safe for the eyes?

OBJECTIVE

Light therapy has become an increasingly popular treatment for depression and a range of other neuropsychiatric conditions. Yet, concerns have been raised about the ocular safety of light therapy.

METHOD

We conducted the first systematic review into the ocular safety of light therapy. A PubMed search on January 4, 2017, identified 6708 articles, of which 161 were full-text reviewed. In total, 43 articles reporting on ocular complaints and ocular examinations were included in the analyses.

RESULTS

Ocular complaints, including ocular discomfort and vision problems, were reported in about 0% to 45% of the participants of studies involving light therapy. Based on individual studies, no evident relationship between the occurrence of complaints and light therapy dose was found. There was no evidence for ocular damage due to light therapy, with the exception of one case report that documented the development of a maculopathy in a person treated with the photosensitizing antidepressant clomipramine.

CONCLUSION

Results suggest that light therapy is safe for the eyes in physically healthy, unmedicated persons. The ocular safety of light therapy in persons with preexisting ocular abnormalities or increased photosensitivity warrants further study. However, theoretical considerations do not substantiate stringent ocular safety-related contraindications for light therapy.

Estrogen receptor mutations and splice variants determined in liquid biopsies from metastatic breast cancer patients

Mutations and splice variants in the estrogen receptor (ER) gene, ESR1, may yield endocrine resistance in metastatic breast cancer (MBC) patients. These putative endocrine resistance markers are likely to emerge during treatment, and therefore, its detection in liquid biopsies, such as circulating tumor cells (CTCs) and cell‐free DNA (cfDNA), is of great interest. This research aimed to determine whether ESR1 mutations and splice variants occur more frequently in CTCs of MBC patients progressing on endocrine treatment. In addition, the presence of ESR1 mutations was evaluated in matched cfDNA and compared to CTCs. CellSearch‐enriched CTC fractions (≥5/7.5 mL) of two MBC cohorts were evaluated, namely (a) patients starting first‐line endocrine therapy (n = 43, baseline cohort) and (b) patients progressing on any line of endocrine therapy (n = 40, progressing cohort). ESR1 hotspot mutations (D538G and Y537S/N/C) were evaluated in CTC‐enriched DNA using digital PCR and compared with matched cfDNA (n = 18 baseline cohort; n = 26 progressing cohort). Expression of ESR1 full‐length and 4 of its splice variants (∆5, ∆7, 36 kDa, and 46 kDa) was evaluated in CTC‐enriched mRNA. It was observed that in the CTCs, the ESR1 mutations were not enriched in the progressing cohort (8%), when compared with the baseline cohort (5%) (P = 0.66). In the cfDNA, however, ESR1 mutations were more prevalent in the progressing cohort (42%) than in the baseline cohort (11%) (P = 0.04). Three of the same mutations were observed in both CTCs and cfDNA, 1 mutation in CTCs only, and 11 in cfDNA only. Only the ∆5 ESR1 splice variant was CTC‐specific expressed, but was not enriched in the progressing cohort. In conclusion, sensitivity for detecting ESR1 mutations in CTC‐enriched fractions was lower than for cfDNA. ESR1 mutations detected in cfDNA, rarely present at the start of first‐line endocrine therapy, were enriched at progression, strongly suggesting a role in conferring endocrine resistance in MBC.

Estrogen receptor mutations and splice variants determined in liquid biopsies from metastatic breast cancer patients

Mutations and splice variants in the estrogen receptor (ER) gene, ESR1, may yield endocrine resistance in metastatic breast cancer (MBC) patients. These putative endocrine resistance markers are likely to emerge during treatment, and therefore, its detection in liquid biopsies, such as circulating tumor cells (CTCs) and cell-free DNA (cfDNA), is of great interest. This research aimed to determine whether ESR1 mutations and splice variants occur more frequently in CTCs of MBC patients progressing on endocrine treatment. In addition, the presence of ESR1 mutations was evaluated in matched cfDNA and compared to CTCs. CellSearch-enriched CTC fractions (≥5/7.5 mL) of two MBC cohorts were evaluated, namely (a) patients starting first-line endocrine therapy (n = 43, baseline cohort) and (b) patients progressing on any line of endocrine therapy (n = 40, progressing cohort). ESR1 hotspot mutations (D538G and Y537S/N/C) were evaluated in CTC-enriched DNA using digital PCR and compared with matched cfDNA (n = 18 baseline cohort; n = 26 progressing cohort). Expression of ESR1 full-length and 4 of its splice variants (∆5, ∆7, 36 kDa, and 46 kDa) was evaluated in CTC-enriched mRNA. It was observed that in the CTCs, the ESR1 mutations were not enriched in the progressing cohort (8%), when compared with the baseline cohort (5%) (P = 0.66). In the cfDNA, however, ESR1 mutations were more prevalent in the progressing cohort (42%) than in the baseline cohort (11%) (P = 0.04). Three of the same mutations were observed in both CTCs and cfDNA, 1 mutation in CTCs only, and 11 in cfDNA only. Only the ∆5 ESR1 splice variant was CTC-specific expressed, but was not enriched in the progressing cohort. In conclusion, sensitivity for detecting ESR1 mutations in CTC-enriched fractions was lower than for cfDNA. ESR1 mutations detected in cfDNA, rarely present at the start of first-line endocrine therapy, were enriched at progression, strongly suggesting a role in conferring endocrine resistance in MBC.

Abstract P1-06-01: Evaluation of subclonality in the CTC and DTC compartment of patients with metastatic breast cancer using low pass whole genome and AmpliSeq panel sequencing

Background

A growing understanding of the molecular biology of cancer and the identification of specific aberrations driving cancer evolution have led to the development of various targeted agents. Tumors can exhibit significant heterogeneity and this may change over time, also as the result of selective pressure. Circulating tumor cells (CTCs), shed from multiple tumor sites, have demonstrated to represent of the overall tumor burden. We report the results of an ongoing comparative study on mutation and copy number profiles of primary and metastatic tissue, CTCs, and synchronously isolated DTCs from metastatic effusions of patients with clinically progressive MBC.

Materials & Methods

CTCs and DTCs were enriched from 7.5 ml blood or effusion using the CellSearch system and were further purified and sorted with the DEPArray system. For this study we isolated both 70 single and 70 pools of 10-200 CTCs or DTCs, in order have enough power to detect 5% subclones and analyse heterogeneity. Single and pooled WBCs were isolated as technical controls. DNA was isolated and amplified using the Ampli1-kit and subjected to Illumina WGS and Ion Torrent AmpliSeq panel sequencing. Fresh frozen tissue from solid metastases and the primary tumor, and bulk CTC (CellSearch Profile) were sequenced as comparators for mutation and copy number profiles. DNA of buffy coat was sequenced to enable germline variant detection. For mutational analysis, only somatic variants with good quality metrics, &gt;20x coverage, variant allele frequencies &gt;10%, and being non-synonymous or splice site variants, were taken into account.

Results

AmpliSeq panel sequencing was performed on 153 unique samples of three patients with a mean coverage depth of 1000x. In patient 1, a PIK3CA hotspot mutation was found clonally in all tumor samples at heterozygous level. Furthermore, various private mutations were found in both CTCs and DTCs, however not in WBC, including several TP53 hotspot mutations. In patient 2, another PIK3CA hotspot was present in all CTCs at heterozygous frequencies. In patient 3, an enormous heterogeneity was observed between all CTC and DTC samples. For patient 3, disease evolution was detected during multiple events of progressive disease over 2 years. At the moment, low pass WGS for CN detection for all samples is being performed and results will be present prior to the SABCS.

Conclusion

Based on the mutational status we conclude that both clonal mutations as well as various private variants are present in single and pools of CTCs and DTCs. In addition to the detection of targetable aberrations, the evaluation of heterogeneity is of clinical importance, as the effect of targeting subclones is currently being explored in clinical trials.

Citation Format: Brouwer A, van Dam P-J, Rutten A, Prové A, Peeters M, Van Laere S, Dirix L. Evaluation of subclonality in the CTC and DTC compartment of patients with metastatic breast cancer using low pass whole genome and AmpliSeq panel sequencing [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-06-01.

Abstract P3-05-10: Evaluation of HER2 expression and amplification on CTCs using DEPArray analysis and sorting followed by FISH

Introduction

In metastatic breast cancer (MBC), discordant expression levels of the human epidermal growth factor receptor 2 (HER2) have been noted between primary tumors (PT) and matched metastatic lesions. Reassessment of HER2 status during treatment decisions in patients with advanced disease might help to optimize outcome. Circulating tumor cells (CTCs) offer the potential to provide a repeatedly accessible source of tumor cells for the real-time assessment of actual tumor characteristics. However, little is known on the concordance of HER2 expression on CTCs measured by immunofluorescence and the amplification status.

Here we report on a preclinical study, using five spiked breast cancer cell lines, comparing semi-quantitative HER2 scoring on CellSearch (Riethdorf 2010) with objective DEPArray analysis, and subsequent FISH analysis on DEPArray-sorted tumor cells. At the moment these data are also being generated for 10 patient CTC samples. Expression and amplification status of CTCs will be compared with primary tumor tissue.

Materials and methods

MDA-MB-436, MCF-7, BT-20, KPL-4, and SKBR3 cells (increasing HER2 status) were spiked into donor blood and subjected to CellSearch enrichment. HER2/FITC intensity was scored manually on the CellSearch analyzer. All cell lines were injected into the DEPArray and exposure settings were optimized (FITC: exposure time 800 ms, gain 5%). These settings are further used for all preclinical and clinical samples. HER2 scoring was based on relative fluorescent units (rfu) of the HER2/FITC signal with background subtraction. Cells were sorted into pure batches of HER2 positive (DAPI+/CK+/HER2+/CD45-) and negative (DAPI+/CK+/HER2-/CD45-) tumor cells. Cytospins were formalin fixed and subjected to DAKO IQFISH.

Results

HER2 expression on CellSearch turned out to be very heterogeneous within the same cell line. DEPArray data was highly reproducible for all cell lines (p&lt;0.001) and also showed a broad range of FITC rfu within the HER2 positive cell lines. Significant differences were observed between every cell line (p&lt;0.001). The SKBR3 cell line sample also harbored a minor population of HER2- cells while this was the most positive cell line. However with FISH analysis, both HER2- and HER2+ SKBR3 cells were highly amplified (absolute HER2 count of 12-20 and HER2/CEN17 ratio of &gt;4). MDA-MB-436 and MCF-7 cells showed no gene amplification on FISH, while in KPL-4 there was a HER2/CEN17 ratio of &gt;2.

Four patient samples with HER2 positive status on CellSearch have been run on the DEPArray. For patient 1, 1005 CTC were analyzed, 32.4% were HER2+. This was 53 (69.8% HER2+), 352 (5.7% HER2+), and 622 (6.7% HER2+) for patient 2-4 respectively. These numbers are comparable with CellSearch analysis.

Discussion

HER2 expression analysis by immunofluorescence is comparable between CellSearch and DEPArray, however DEPArray has the advantage that it is user-independent and highly reproducible. Furthermore, CTCs can be sorted into pure batches for downstream analysis. The FISH technique on DEPArray sorted cells is now optimized and will be used to determine the correlation between the immunofluorescent HER2 scoring and the actual amplification status of the CTCs. These data will be incorporated prior to upcoming SABCS.

Citation Format: Brouwer A, Verhoest F, Vermeulen P, Rutten A, Prové A, Van Laere S, Peeters M, Dirix L. Evaluation of HER2 expression and amplification on CTCs using DEPArray analysis and sorting followed by FISH [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-05-10.

Urgent request on avian influenza

Highly pathogenic avian influenza (HPAI) H5N8 is currently causing an epizootic in Europe, infecting many poultry holdings as well as captive and wild bird species in more than 10 countries. Given the clear clinical manifestation, passive surveillance is considered the most effective means of detecting infected wild and domestic birds. Testing samples from new species and non‐previously reported areas is key to determine the geographic spread of HPAIV H5N8 2016 in wild birds. Testing limited numbers of dead wild birds in previously reported areas is useful when it is relevant to know whether the virus is still present in the area or not, e.g. before restrictive measures in poultry are to be lifted. To prevent introduction of HPAIV from wild birds into poultry, strict biosecurity implemented and maintained by the poultry farmers is the most important measure. Providing holding‐specific biosecurity guidance is strongly recommended as it is expected to have a high impact on the achieved biosecurity level of the holding. This is preferably done during peace time to increase preparedness for future outbreaks. The location and size of control and in particular monitoring areas for poultry associated with positive wild bird findings are best based on knowledge of the wider habitat and flight distance of the affected wild bird species. It is recommended to increase awareness among poultry farmers in these established areas in order to enhance passive surveillance and to implement enhanced biosecurity measures including poultry confinement. There is no scientific evidence suggesting a different effectiveness of the protection measures on the introduction into poultry holdings and subsequent spread of HPAIV when applied to H5N8, H5N1 or other notifiable HPAI viruses.

This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2016.EN-1142/full

Prognostic Impact of HER2 and ER Status of Circulating Tumor Cells in Metastatic Breast Cancer Patients with a HER2-Negative Primary Tumor

BACKGROUND

Preclinical and clinical studies have reported that human epidermal growth factor receptor 2 (HER2) overexpression yields resistance to endocrine therapies. Here the prevalence and prognostic impact of HER2-positive circulating tumor cells (CTCs) were investigated retrospectively in metastatic breast cancer (MBC) patients with a HER2-negative primary tumor receiving endocrine therapy. Additionally, the prevalence and prognostic significance of HER2-positive CTCs were explored in a chemotherapy cohort, as well as the prognostic impact of the estrogen receptor (ER) CTC status in both cohorts.

METHODS

Included were MBC patients with a HER2-negative primary tumor, with ≥1 detectable CTC, starting a new line of treatment. CTCs were enumerated using the CellSearch system, characterized for HER2 with the CellSearch anti-HER2 phenotyping reagent, and characterized for ER mRNA expression. Primary end point was progression-free rate after 6 months (PFR6months) of endocrine treatment in HER2-positive versus HER2-negative CTC patients.

RESULTS

HER2-positive CTCs were present in 29% of all patients. In the endocrine cohort (n=72), the PFR6months was 53% for HER2-positive versus 68% for HER2-negative CTC patients (P=.23). In the chemotherapy cohort (n=82), no prognostic value of HER2-positive CTCs on PFR6months was observed either. Discordances in ER status between the primary tumor and CTCs occurred in 25% of all patients but had no prognostic value in exploratory survival analyses.

CONCLUSION

Discordances regarding HER2 status and ER status between CTCs and the primary tumor occurred frequently but had no prognostic impact in our MBC patient cohorts.

Bovine TB surveillance in Great Britain in 2014

This report, provided by the APHA, summarises the key descriptive epidemiological parameters of bovine TB in cattle in Great Britain from January 1 to December 31, 2014. It summarises some of the temporal trends observed over a longer period and highlights some differences and similarities between Scotland, Wales and the three bovine TB risk areas of England. It updates the previous annual summaries for 2012 and 2013, also published inVeterinary Record(VR, June 14, 2014, vol 174, pp 600-604; March 28, 2015, vol 176, pp 326-330).

Abstract P3-04-01: Manual and digital detection of HER2 status of 2721 circulating tumour cells in patients with metastatic breast cancer

Introduction:

In metastatic breast cancer (MBC), discordant expression levels of the human epidermal growth factor receptor 2 (HER2) have been noted between primary tumours (PT) and matched metastatic lesions (Meta). Therefore reassessment of this predictive marker at time of metastatic disease might help to optimize treatment. Circulating tumour cells (CTCs) offer the potential to provide a repeatedly accessible source of tumour cells for the real-time assessment of actual tumour characteristics.

Here we report on a retrospective study analysing over two and a half thousand CTCs in order to evaluate the inter-observer variability when using the semi-quantitative scale (0-3+) described by Riethdorf in 2010. Furthermore we designed a digital scoring system using 13 parameters selected by ImageJ. HER2 status in CTCs was compared to PT and/or Meta of patients with MBC.

Materials and methods:

65 patients starting first or second line systemic therapy for MBC and harbouring more than 5 CTC/7.5 mL blood were selected. HER2 status of 2721 CTCs was determined by immunofluorescence using the CellSearch system. HER2 status of the solid lesions was determined by IHC or FISH. Inter-observer variability was calculated using the Kendalls tau tests. 284 CTCs were analysed with the digital scoring system using ImageJ 'plot profile' and 'analyse particles'. Selected parameters comprise cell size, mean and maximum intensity of the cell and its surrounding, and both ratio's and differences of the aforementioned. Dissimilarity matrix was calculated using Pearson Correlation-Distance.

Results:

Of 2721 CTCs, 1485 cells (55%) were scored 0+ and 2263 cells (83%) were found to be HER2- (0+ or 1+) by both observers. 458 cells (17%) were scored HER2+ (2+ or 3+) by at least one of the observers, however only 175 (6%) by both observers. Inter-observer variability was 0.703, but when omitting the usually undebatable 0+ cells, this variability showed to be 0.278.

HER2 scoring of CTC by two observers. HER2- (0+/1+)HER2+ (2+/3+)HER2- (0+/1+)2263 (83%)131 (4.8%)HER2+ (2+/3+)152 (5.6%)175 (6.4%)

24 of 65 patients had at least 80% 0+ CTCs (≥96% HER2- cells). Of these patients, 5 were HER2+ based on their PT. Oppositely, 10 and 20 patients harboured at least 40% and 10% HER2+ CTCs respectively. From these 20 patients only 10 were diagnosed with HER2+ disease on PT or Meta and 1 was shifted form HER2- PT to HER2+ Meta.

The digital scoring system was able to identify four groups with different HER2 expression levels. When comparing the identified clusters with the manually scored cells the two moderately related clusters showed to contain almost only 2+ and 3+ CTCs. A very isolated cluster contained almost solely 0+ CTCs.

Discussion:

The manual scoring system showed to be feasible, however we noticed that there are some discrepancies regarding the scoring of 1+ to 3+ cells. The digital scoring is able to predict the outcome and can by itself cluster CTCs into 4 groups. It strongly distinguishes between the HER2+ and HER2- cells. HER2+ status can change during disease progression, both with gain and loss of HER2 positivity. This can be monitored using CTCs.

Citation Format: Brouwer A, van de Wiel M, Peeters B, van Dam P-J, Vermeulen P, Peeters M, Van Laere S, Peeters D, Dirix L. Manual and digital detection of HER2 status of 2721 circulating tumour cells in patients with metastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-04-01.

Assessing the impact of a cattle risk-based trading scheme on the movement of bovine tuberculosis infected animals in England and Wales

The adoption of bovine tuberculosis (bTB) risk-based trading (RBT) schemes has the potential to reduce the risk of bTB spread. However, any scheme will have cost implications that need to be balanced against its likely success in reducing bTB. This paper describes the first stochastic quantitative model assessing the impact of the implementation of a cattle risk-based trading scheme to inform policy makers and contribute to cost-benefit analyses. A risk assessment for England and Wales was developed to estimate the number of infected cattle traded using historic movement data recorded between July 2010 and June 2011. Three scenarios were implemented: cattle traded with no RBT scheme in place, voluntary provision of the score and a compulsory, statutory scheme applying a bTB risk score to each farm. For each scenario, changes in trade were estimated due to provision of the risk score to potential purchasers. An estimated mean of 3981 bTB infected animals were sold to purchasers with no RBT scheme in place in one year, with 90% confidence the true value was between 2775 and 5288. This result is dependent on the estimated between herd prevalence used in the risk assessment which is uncertain. With the voluntary provision of the risk score by farmers, on average, 17% of movements was affected (purchaser did not wish to buy once the risk score was available), with a reduction of 23% in infected animals being purchased initially. The compulsory provision of the risk score in a statutory scheme resulted in an estimated mean change to 26% of movements, with a reduction of 37% in infected animals being purchased initially, increasing to a 53% reduction in infected movements from higher risk sellers (score 4 and 5). The estimated mean reduction in infected animals being purchased could be improved to 45% given a 10% reduction in risky purchase behaviour by farmers which may be achieved through education programmes, or to an estimated mean of 49% if a rule was implemented preventing farmers from the purchase of animals of higher risk than their own herd. Given voluntary trials currently taking place of a trading scheme, recommendations for future work include the monitoring of initial uptake and changes in the purchase patterns of farmers. Such data could be used to update the risk assessment to reduce uncertainty associated with model estimates.

Abstract P4-01-14: Whole exome sequencing of circulating and disseminated tumour cells in patients with metastatic breast cancer

Introduction:

Circulating tumour cells (CTC) found in the blood of patients with cancer offer the potential to provide a repeatedly accessible source of tumour cells for the real-time assessment of tumour characteristics in patients with metastatic breast cancer (MBC). Questions remain to what extent CTC are truly representative of the actually present tumour mass in a patient at a specific moment in time and the molecular heterogeneity within the CTC population is only now being explored. Here, we report on the first results of an ongoing comparative study of mutation profiles of CTC and synchronously isolated disseminated tumour cells (DTC) from metastatic effusions or biopsies of solid metastases of patients with clinically progressive MBC.

Materials and methods:

For this project CTC are isolated from 7.5 ml blood samples of patients with MBC using the CellSearch system. CellSearch enriched CTC samples are subsequently further purified and sorted into several batches of 1-125 CTC per patient using the DEPArray system. DNA is isolated and amplified using the Ampli1 whole genome amplification (WGA) kit and subjected to whole exome paired-end sequencing (WES). DTC from metastatic effusions, fresh frozen tissue from solid metastases or the primary tumour, or - in patients with extremely high CTC counts (&gt;10.000/7.5 ml) - pooled CTC from the CellSearch Profile sample, are sequenced as a comparator for mutation profiles. DNA from the buffy coat of white blood cells are sequenced to enable somatic mutation analysis.

Results:

Eight samples of 1-125 CTC and a CellSearch Profile sample of one patient with MBC who had ca. 30.000 CTC/7.5 ml of blood (patient 1) and 4 CTC samples of 5-10 CTC, 2 temporally matched DTC samples of 10 and 20 DTC from a pleural effusion and a fresh frozen tissue sample of the primary tumour of a second patient (patient 2) have been sequenced so far. Average base coverages were 13.6x (patient 1) and 11.8x (patient 2) for CTC/DTC samples and 175x and 120x for the CellSearch profile sample (patient 1) and the primary tumour sample (patient 2) respectively. Between 29.64% and 53.57% of the exomes of amplification products of CTC/DTC DNA were uncovered, probably due to technical limitations of the WGA procedure. Overall, if adequately covered, good concordances were observed for variants identified with MuTect in 28 frequently mutated genes in breast cancer between samples of amplification products of 1-125 CTC and the CellSearch Profile sample of patient 1. In patient 2, the same H1047R PIK3CA mutation was identified in the primary tumour and all CTC and DTC samples. In-depth analyses of the full exome data are being conducted.

Discussion:

Our data provide insight into clinically relevant questions to what extent CTC reflect mutational profiles in temporally matched metastatic tumour cells, and – by analysing multiple CTC samples of the same patient – genetic heterogeneity between CTC in patients with MBC. Sample accrual and analysis is being expanded and updated results will be presented at the conference.

Citation Format: Dieter JE Peeters, Ken Op De Beeck, Anja Brouwer, Geert Vandeweyer, Patrick Pauwels, Marc Peeters, Peter B Vermeulen, Peter A van Dam, Steven J Van Laere, Guy Van Camp, Luc Y Dirix. Whole exome sequencing of circulating and disseminated tumour cells in patients with metastatic breast cancer [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 P4-01-14.

Tuberculous mastitis presenting as a lump: a mimicking disease in a pregnant woman case report and review of literature

Tuberculosis (TB) of the breast is a rare entity, and can be confused with many other breast disorders, like mamma carcinoma or inflammatory breast cancer. When finding granulomatous mastitis (GM) on histology, it is important to make a differential diagnosis and seek actively for clues on the presence of tuberculosis, sarcoidosis, Wegener's granulomatosis, or idiopathic granulomatous mastitis, since treatment strategies differ and maltreatment has major implications on morbidity and mortality. An extensive clinical evaluation, laboratory work up, and imaging will lead in most cases to the right diagnosis. Anti-tuberculous therapy is the core treatment for breast TB, and surgery is indicated for extensive or persistent residual disease. Here we present a case of tuberculous mastitis and a review of literature on GM.

PAH-CALUX, an optimized bioassay for AhR-mediated hazard identification of polycyclic aromatic hydrocarbons (PAHs) as individual compounds and in complex mixtures

Polycyclic aromatic hydrocarbons (PAHs) represent a class of ubiquitously occurring environmental compounds that are implicated in a wide range of toxicological effects. Routine measurement of PAH contamination generally involves chemical analytical analysis of a selected group of representatives, for example, EPA-16, which may result in underestimation of the PAH-related toxicity of a sample. Many high molecular weight PAHs are known ligands of the aryl hydrocarbon receptor (AhR), a nuclear receptor that mediates toxic effects related to these compounds. Making use of this property we developed a PAH CALUX assay, a mammalian, H4IIe- cell-based reporter assay for the hazard identification of total PAH mixtures. The PAH CALUX reporter cell line allows for specific, rapid (4 h exposure time) and reliable quantification of AhR-induced luciferase induction relative to benzo[a]pyrene (BaP), which is used as a positive reference PAH congener. Full dose response relationships with inductions over 100-fold were reached within only 2 h of exposure to BaP. The PAH CALUX is highly sensitive, that is, using a 4 h exposure time, a limit of detection (LOD) of 5.2 × 10(-11) M BaP was achieved, and highly accurate, that is, a repeatability of 5.9% and a reproducibility of 6.6% were established. Screening of a selection of PAHs that were prioritized by the European Union and/or the U.S. Environmental Protection Agency showed that the PAH CALUX bioassay has a high predictability, particularly for carcinogenic PAHs. Experiments with synthetic mixtures and reference materials containing complex PAH mixtures show the suitability of the assay for these types of applications. Moreover, the presented results suggest that application of the PAH CALUX will result in a lower risk of underestimation of the toxicity of a sample than chemical analytical approaches that focus on a limited set of prioritized compounds.

Epidemic threats to the European Union: expert views on six virus groups

In recent years, several animal disease epidemics have occurred within the European Union (EU). At the 4th Annual Meeting of the EPIZONE network (7-10 June 2010, St. Malo, France), an interactive session was run to elicit the opinions of delegates on a pre-defined list of epidemic threats to the EU. Responses from over 190 delegates, to questions relating to impact and likelihood, were used to rank six virus groups with respect to their perceived threat now (2010) and in 2020. The combined opinions of all delegates suggested that, from the pre-selected list of virus groups, foot-and-mouth disease and influenza are currently of most concern. Delegates thought that influenza would be less of a threat and zoonotic arboviruses would be more of a threat in 2020. Although the virus group rankings should not be taken as definitive, the results could be used in conjunction with experimental and field data, by scientists, policy-makers and stakeholders when assessing and managing risks associated with these virus groups.

Influence of prenatal organohalogen levels on infant male sexual development: sex hormone levels, testes volume and penile length

BACKGROUND

Prenatal exposure to endocrine disruptors, like organohalogen compounds (OHCs), might be responsible for the increased aberrations in human male sexual development (hypospadias, cryptorchidism, testicular cancer and fall in sperm count) observed over the past decades. This development is established during fetal life, and reflected in sex hormone levels, testes volume and penile length post-partum. The present study investigates the correlation between prenatal OHC levels and male sexual development outcomes.

METHODS AND RESULTS

Levels of eight neutral [2,2'-bis-(4-chlorophenyl)-1,1'-dichloroethene (4,4'-DDE), 2,2',4,4',5,5'-hexachlorobiphenyl, 2,2',4,4'-tetrabromodiphenyl ether (BDE)-47, -99, -100, -153, -154 and 1,2,5,6,9,10-hexabromocyclododecane, HBCDD] and four phenolic [(pentachlorophenol (PCP), 4OH-CB-107 (4-hydroxy-2,3,3',4',5-pentachlorobiphenyl), -146 and -187)] OHCs were determined in 55 maternal serum samples taken at 35 weeks of pregnancy. Eight sex development-related hormones [testosterone, free testosterone, sex hormone-binding globulin (SHBG); LH, FSH, estradiol (E(2)), free E(2) (FE(2)) and inhibin B (InhB)] were determined in their sons at 3 months of age, and testes volume and penile length at 3 and 18 months of age. The following prenatal OHC levels correlated significantly with sex hormone levels: PCP with SHBG and InhB (ρ = 0.30 and -0.43, respectively), 4OH-CB-107 with testosterone (ρ = 0.31) and BDE-154 with FE(2), E(2) and InhB (ρ = 0.49, 0.54 and 0.34, respectively). BDE-154 levels correlated positively with testes volume at 18 months of age (ρ = 0.34).

CONCLUSIONS

Prenatal OHC exposure is correlated with aspects of sexual development outcome in boys up to 18 months of age.

Impact of climate change on risk of incursion of Crimean-Congo haemorrhagic fever virus in livestock in Europe through migratory birds

AIMS

To predict the risk of incursion of Crimean-Congo haemorrhagic fever virus (CCHFV) in livestock in Europe introduced through immature Hyalomma marginatum ticks on migratory birds under current conditions and in the decade 2075-2084 under a climate-change scenario.

METHODS AND RESULTS

A spatial risk map of Europe comprising 14 282 grid cells (25 × 25 km) was constructed using three data sources: (i) ranges and abundances of four species of bird which migrate from sub-Saharan Africa to Europe each spring, namely Willow warbler (Phylloscopus trochilus), Northern wheatear (Oenanthe oenanthe), Tree pipit (Anthus trivialis) and Common quail (Coturnix coturnix); (ii) UK Met Office HadRM3 spring temperatures for prediction of moulting success of immature H. marginatum ticks and (iii) livestock densities. On average, the number of grid cells in Europe predicted to have at least one CCHFV incursion in livestock in spring was 1·04 per year for the decade 2005-2014 and 1·03 per year for the decade 2075-2084. In general with the assumed climate-change scenario, the risk increased in northern Europe but decreased in central and southern Europe, although there is considerable local variation in the trends.

CONCLUSIONS

The absolute risk of incursion of CCHFV in livestock through ticks introduced by four abundant species of migratory bird (totalling 120 million individual birds) is very low. Climate change has opposing effects, increasing the success of the moult of the nymphal ticks into adults but decreasing the projected abundance of birds by 34% in this model.

SIGNIFICANCE AND IMPACT OF THE STUDY

For Europe, climate change is not predicted to increase the overall risk of incursion of CCHFV in livestock through infected ticks introduced by these four migratory bird species.

Evaluation of tumour promoting potency of fish borne toxaphene residues, as compared to technical toxaphene and UV-irradiated toxaphene

In this study the potential impact of food chain-based biotransformation and physico-chemical weathering of toxaphene on its tumour promoting potential was investigated in vitro and in vivo. Human exposure to toxaphene is mainly through consumption of contaminated fish, therefore fish-borne residues of toxaphene (cod liver extract, CLE) were prepared by exposing cod to technical toxaphene (TT) for 63 days. UV-irradiated toxaphene (uvT) was included to represent a physico-chemical weathered toxaphene mixture. In vitro, TT, uvT and CLE all showed a dose- and time-dependent inhibition of gap junctional intercellular communication (GJIC) with a relative potency of CLE>TT=uvT. Tumour promoting potency was further studied in vivo in a medium term two-stage initiation/promotion bioassay in female Sprague-Dawley rats, using an increase in altered hepatic foci positive for glutathione-S-transferase-P (AHF-GST-P) as read out. No increase in AHF-GST-P occurred following exposure to either TT, uvT, or CLE, except for the positive control group (2,3,7,8-TCDD). Based on this study the no observed adverse effect level (NOAEL) for tumour promoting potency is at least 12.5mg/kg/week, or higher for CLE. Considering current human exposure levels in Europe it is doubtful that consumption of fish at current levels of toxaphene contamination give rise to human health risk.

Bio/chemical analysis of dioxin-like compounds in sediment samples from Osaka Bay, Japan

The combinatorial bio/chemical investigation of sediments (six surface samples and one core sample) from Osaka Bay, Japan was conducted to clarify the horizontal and vertical distribution profiles of persistent organic pollutants in the sediments. Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and polybrominated diphenylethers (PBDEs) were determined by chemical analysis and compared to bioassay results using H4IIE-luc/Dioxin Responsive-Chemical Activated LUciferase eXpression (DR-CALUX). For surface sediments, World Health Organization-toxicity equivalent (WHO-TEQ) values ranged from 1.8 to 92 pg g(-1) dry weight and the bioassay-TEQ (CALUX-TEQ) values (3.7-140 pg g(-1) dry weight) yielded significant correlation with them (r2 = 0.96). On the other hand, correlation between both TEQs (for WHO-TEQ, 5.5-47 and for CALUX-TEQ, 27-76 pg g(-1) dry weight) for core samples was not so good (r2 = 0.46). Comparing the vertical profiles of CALUX-TEQ and WHO-TEQ, they were different in that WHO-TEQ reached the maximum in the 1957 core section, while CALUX-TEQ reached in the 1984 core section. CALUX-TEQ values were 1-5-fold more than WHO-TEQ values in all the surface and core samples. CALUX-TEQ values were calculated for PBDE and PBDD/F concentrations, employing their CALUX toxicity equivalent factors (CALUX-TEFs). The estimated CALUX-TEQ values obtained for the brominated compounds could explain for 11% on average (range 4.7-31%) of the experimentally obtained CALUX-TEQ values in the investigated surface sediments.

[Antithrombotic therapy after myocardial infarction: arguments for the use of acetylsalicylic acid and coumarin derivatives]

Patients who survived myocardial infarction and who are being treated with the current optimal therapy (antithrombotics, statins and beta-blockers), have a 10-20% chance of death, re-infarction and stroke within in the first year. A possible explanation for this could be an increased activation and generation ofthrombin for at least 6 months following the cardiovascular event preceding preventative therapy. Acetylsalicylic acid and clopidogrel do not affect activation by thrombin of the platelet aggregation and the clotting cascade. The additional use of cumarin derivatives could therefore reduce the chance of recurring thrombotic events, and subsequently improve prognosis. Since the nineteen-nineties several randomised trials have been conducted to study the clinical relevance ofcumarin derivatives both with and without acetylsalicylic acid, in patients who had had a myocardial infarction. The conclusions of these studies were not unambiguous. If the international normalized ratio (INR) was kept > 2 for a long period, by means of frequent check-ups and effective dosage adjustment, the chance of death, recurrent myocardial infarction or stroke was 30-50% lower than when acetylsalicylic acid only was used. The risk of bleeding was raised by 2-4 times, but there were no life-threatening episodes of bleeding. In view of the recent development of anticoagulant agents, for which monitoring seems to be becoming unnecessary, identification of patients who would benefit most from a combined antithrombotic strategy is warranted.

Comparison of dioxin and PCB concentrations in human breast milk samples from Hong Kong and the Netherlands

The adverse effects of dioxins and polychlorinated biphenyls (PCBs) on human health are of increasing concern. These lipophilic compounds are concentrated through the food chain and are present in human milk. This study compares PCB levels in human milk samples from Hong Kong and Dutch mothers. Ten breast milk samples from Hong Kong and 10 from the Netherlands were collected during home visits between 2 and 6 weeks postpartum. Total toxic equivalence (TEQ) of dioxin and PCBs were determined using the DR-CALUX(R) bioassay. The total dioxin and PCB levels in breast milk samples for Hong Kong ranged from 3.1 to 29.9 pg TEQ g(-1) lipid and for the Netherlands from 8.9 to 89.5 pg TEQ g(-1) lipid. Despite Hong Kong's high degree of industrialization, the levels of dioxin and PCBs were fourfold lower in the Hong Kong than in the Dutch samples. This may be due to a lower dietary intake of dioxins and PCBs in Hong Kong because of lower background levels of these contaminants or to different food habits.

Development and validation of an average mammalian estrogen receptor-based QSAR model

Development and evaluation of quantitative structure activity relationships (QSARs) for predicting estrogen receptor binding from chemical structure requires reliable algorithms for three-dimensional (3D) QSAR analysis and establishment of structurally diverse training sets of chemicals whose modes of action and measures of potency are well defined. One approach to selecting an appropriate training set is to minimize the biological variability in the model development, by using structurally restricted data sets. A second approach is to extend the structural diversity of chemicals at the cost of increased variability of biological assays. In this study, the second approach was used by organizing a training set of 151 chemicals with measured human alpha Estrogen Receptor (ERalpha), mouse uterine, rat uterine, and MCF7 cell Relative Binding Affinities (RBAs). The structurally augmented training set was submitted to a 3D pattern recognition analysis to derive a model for average mammalian ER binding affinity by employing the COmmon REactivity PAttern (COREPA) approach. Elucidation of this pattern required examination of the conformational flexibility of the compounds in an attempt to reveal areas in the multidimensional descriptor space, which are most populated by the conformers of the biologically active molecules and least populated by the inactive ones. The approach is not dependent upon a predetermined and specified toxicophore or an alignment of conformers to a lead compound. Reactivity patterns associated with mammalian ER binding affinity were obtained in terms of global nucleophilicity (E(HOMO)), interatomic distances between nucleophilic sites, and local nucleophilicity (charges or delocalizabilities) of those sites. Based on derived patterns, descriptor profiles were established for identifying and ranking compounds with RBA of > 150, 150-10, 10-1 and 1-0.1% relative to 17beta-estradiol. Specificity of reactivity profiles was found to increase gradually with increasing affinities associated with RBAs ranges under study. Using the results of this analysis, an exploratory expert system was developed for use in ranking relative mammalian ER binding affinity potential for large chemical data sets. The validity of the RBA predictions were confirmed by independent development and comparison with measured RBA values.

EU Drinking Water Directive reference methods for enumeration of total coliforms and Escherichia coli compared with alternative methods

AIMS

The reference methods for enumeration of total coliforms and Escherichia coli as stated in the European Drinking Water Directive were compared with alternative methods.

METHODS AND RESULTS

Laboratories used the reference method on Lactose TTC agar (LTTC), the Colilert/18 system, Laurysulphate Agar (LSA), Chromocult Coliform Agar and the E. coli Direct Plating (DP) method. They enumerated more total coliforms on LTTC than on LSA.

CONCLUSIONS

LTTC is suitable for analysis of very clean water samples only, due to heavy background growth. Colilert/18 is a good alternative but it enumerates a broader group of total coliforms, resulting in higher counts. The DP method appeared to be the best choice for enumeration of E. coli because Colilert/18 produces lower counts and false-negative results.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows the limitations of the EU reference method on LTTC due to lack of selectivity and suggests alternative methods for the enumeration of total coliforms and E. coli.

Severe nasal clefting and abnormal embryonic apoptosis in Alx3/Alx4 double mutant mice

A group of mouse aristaless-related genes has been implicated in functions in the development of the craniofacial skeleton. We have generated an Alx3 mutant allele in which the lacZ coding sequence is inserted in-frame in the Alx3 gene and the sequences encoding the conserved protein domains are deleted. Mice homozygous for this null allele are indistinguishable from wild-type mice. Compound mutants of Alx3 and Alx4, however, show severe craniofacial abnormalities that are absent in Alx4 single mutants. Alx3/Alx4 double mutant newborn mice have cleft nasal regions. Most facial bones and many other neural crest derived skull elements are malformed, truncated or even absent. The craniofacial defects in Alx3/Alx4 double mutant embryos become anatomically manifest around embryonic day 10.5, when the nasal processes appear to be abnormally positioned. This most probably leads to a failure of the medial nasal processes to fuse in the facial midline and subsequently to the split face phenotype. We detected a significant increase in apoptosis localised in the outgrowing frontonasal process in embryonic day 10.0 double mutant embryos, which we propose to be the underlying cause of the subsequent malformations.

The risk of endometriosis and exposure to dioxins and polychlorinated biphenyls: a case-control study of infertile women

BACKGROUND

A case-control study was designed to determine the possible association between chronic exposure to dioxins and polychlorinated biphenyls (PCBs), and the occurrence of endometriosis. The study group consisted of 42 infertile endometriosis cases and 27 mechanical infertile controls, both groups attending one of the collaborating Centres for Reproductive Medicine, enrolled between 1996-1998.

METHODS

Exposure assessment to dioxin-like compounds was determined through CALUX (chemical-activated luciferase gene expression)-bioassay to measure dioxin-like total toxic equivalents (dioxins and co-planar PCBs), whereas non-co-planar PCBs were determined through chemical analysis.

RESULTS

No association was found between median dioxin-like total toxic equivalents (TEQ) and the occurrence of endometriosis in infertile women [cases (n = 34): 29; controls (n = 27): 24; NS]. When patients were subdivided based on an arbitrary cut-off value of 100 pg TEQ/g serum lipids, no statistically significant association between very high exposure to dioxin-like compounds and endometriosis was found [crude odds ratio (OR) = 4.33; confidence interval (CI) 0.49-38.19; NS]. After adjusting for body mass index, and alcohol consumption, the risk increased slightly to OR = 4.6 (CI 0.48-43.62; NS). There was no confounding by age, ovulatory dysfunction, caffeine intake, smoking or exposure to non-co-planar PCBs.

CONCLUSIONS

The study results showed no statistically significant association between exposure to dioxin-like compounds and the occurrence of endometriosis in infertile women.

Fenamates: a novel class of reversible gap junction blockers

The effect of fenamates on gap junctional intercellular communication was investigated in monolayers of normal rat kidney (NRK) fibroblasts and of SKHep1 cells overexpressing the gap junction protein connexin43 (Cx43). Using two different methods to study gap junctional intercellular communication, single electrode voltage-clamp step response measurements and dye microinjection, we show that fenamates are reversible blockers of Cx43-mediated intercellular communication. After adding fenamates to a confluent monolayer of electrically coupled NRK fibroblasts, the voltage step-induced capacitive current transient changed from a transient characteristic for charging multiple coupled cell capacitances to one characteristic for a single cell in isolation. The capacitance of completely uncoupled cells was 19.7 +/- 1.0 pF (mean +/- S.E.M.; n = 11). Junctional conductance between the patched cell and the surrounding cells in the monolayer changed from >140.7 +/- 9.6 nS (mean +/- S.E.M.; n = 14) to <1.4 +/- 0.4 nS (mean +/- S.E.M.; n = 11) after uncoupling. Electrical coupling could be restored to >51.8 +/- 4.2 nS (mean +/- S.E.M.; n = 11) by washout of the fenamates. Voltage-clamp step response measurements showed that the potency of fenamates in inhibiting electrical coupling decreases in the order meclofenamic acid > niflumic acid > flufenamic acid. The half-maximal concentration determined by dye-coupling experiments was 25 and 40 microM for meclofenamic acid and flufenamic acid, respectively. Inhibition of gap junctional communication by fenamates did not involve changes in intracellular calcium or pH, and was unrelated to protein kinase C activity or an inhibition of cyclooxygenase activity. Voltage-clamp step response measurements in confluent monolayers of SKHep1 cells that had been stably transfected with Cx43 revealed that fenamates are potent blockers of Cx43-mediated intercellular communication. In conclusion, fenamates represent a novel class of reversible gap junction blockers that can be used to study the role of Cx43-mediated gap junctional intercellular communication in biological processes.