First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9  GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36  GeV/c^{2}, rejecting cross sections above 9.2×10^{-48}  cm at the 90% confidence level.

Nanopore sequencing of the glucocerebrosidase (GBA) gene in a New Zealand Parkinson's disease cohort

INTRODUCTION

Bi-allelic mutations in the gene for glucocerebrosidase (GBA) cause Gaucher disease, an autosomal recessive lysosomal storage disorder. Gaucher disease causing GBA mutations in the heterozygous state are also high risk factors for Parkinson's disease (PD). GBA analysis is challenging due to a related pseudogene and structural variations (SVs) that can occur at this locus. We have applied and refined a recently developed nanopore DNA sequencing method to analyze GBA variants in a clinically assessed New Zealand longitudinal cohort of PD.

METHOD

We examined amplicons encompassing the coding region of GBA (8.9 kb) from 229 PD cases and 50 healthy controls using the GridION nanopore sequencing platform, and Sanger validation.

RESULTS

We detected 23 variants in 21 PD cases (9.2% of patients). We detected modest PD risk variant p.N409S (rs76763715) in one case, p.E365K (rs2230288) in 12 cases, and p.T408 M (rs75548401) in seven cases, one of whom also had p.E365K. We additionally detected the possible risk variants p.R78C (rs146774384) in one case, p.D179H (rs147138516) in one case which occurred on the same haplotype as p.E365K, and one novel variant c.335C > T or p.(L335 = ), that potentially impacts splicing of GBA transcripts. Additionally, we found a higher prevalence of dementia among patients with GBA variants.

CONCLUSION

This work confirmed the utility of nanopore sequencing as a high-throughput method to identify known and novel GBA variants, and to assign precise haplotypes. Our observations may contribute to improved understanding of the effects of variants on disease pathogenesis, and to the development of more targeted treatments.

P822Statin treatment in symptomatic patients with non-obstructive coronary artery disease reduces the risk of all-cause mortality

Introduction

Symptomatic patients with non-obstructive coronary artery disease (NOCAD; stenosis >0% <50%) have a worse prognosis and an increased risk for all-cause mortality compared with age-matched controls. Currently, treatment of these patients is empiric, and secondary preventive measures are less often implemented. The goal of the study was to examine whether statin prescription has an impact on all-cause mortality in symptomatic NOCAD patients, and which factors influence statin prescription in patients with NOCAD.

Methods

We examined 4039 symptomatic patients who presented either with stable angina (SA) or an acute coronary syndrome (ACS) who underwent coronary angiography; 1582 had angiographically normal coronary arteries, 2457 had minimal disease (NOCAD). The comparison group consisted of 2998 patients with stable obstructive CAD (stenosis ≥50%). Patients had at least one lipid panel tested between April 1, 2010 to March 31, 2014. We examined the rate of statin prescription amongst the groups, as well as predictors of all-cause mortality and statin treatment.

Results

Symptomatic patients with NOCAD are less likely to receive statin therapy (60.4%) compared to patients with obstructive CAD (87.3%). After one, three and five year(s), LDL levels in NOCAD patients are higher than in CAD patients (2.21±0.88mmol/l vs. 1.84mmol/l±0.77mmol/l after 1 year). Statin treatment was associated with a significantly lower risk of all-cause mortality in NOCAD (HR 0.64 (0.44–0.95)), as well as in CAD (HR 0.44 (0.31–0.62)), but not in patients with normal coronaries HR 0.55 (0.27–1.15)). Sex, age and the presence of other cardiovascular risk factors influenced the prescription of statin therapy in the first 5 years after initial diagnosis of NOCAD- older patients with diabetes and hypertension were more likely to receive statin therapy. Women received statin therapy to a lower percentage than men in the NOCAD group (year 1: men 62.9% vs, women 56.9%; p=0.003). No effect of cardiovascular risk factors, age or sex on statin prescription was seen in the CAD group or patients with normal coronaries.

Conclusion

Statin therapy reduces the risk of all-cause mortality in symptomatic patients with NOCAD. In spite of this benefit, patients with NOCAD, and especially women, are less likely to receive secondary-preventive statin therapy.

Parkinson's in the oldest old: Impact on estimates of future disease burden

BACKGROUND

Traditionally the risk of Parkinson's has been considered to increase monotonically with age, although there is evidence that prevalence and incidence may decrease in the oldest old. To examine this further we estimated the national prevalence and incidence of Parkinson's in New Zealand, using drug-tracing methods, to examine the relationship of Parkinson's with sex and age up to 100+.

METHODS

Information on Parkinson's-related medications was extracted from the national pharmaceutical database of community-dispensed medications from 2005 to 2014. Diagnoses for a large subset of individuals were independently determined through national mortality and hospital admissions datasets. We used a Bayesian model, accommodating diagnostic uncertainty and bias, to estimate the number of people with Parkinson's.

RESULTS

The 2013 prevalence of Parkinson's in New Zealand was 210 per 100 000 population (95% uncertainty interval 208-212) with age-standardized prevalence rates higher for males (ratio 1.6:1). Incidence was 31 per 100 000 person-years (95% uncertainty interval 30-32), also higher in males (ratio 1.8:1). Incidence and prevalence by age increased exponentially until 75 years, peaked at 85 years, and then dropped sharply.

CONCLUSIONS

The prevalence of Parkinson's in New Zealand is expected to double over a 25-year period but then increase at a slower rate due to the drop-off in prevalence and incidence in the oldest old. The findings suggest that Parkinson's disease is not an aging-dependent but an age-dependent disorder.

Quality-of-life aspects in idiopathic epilepsy in dogs

Quality of life (QoL) plays a significant role in the treatment of dogs with idiopathic epilepsy (IE), yet is so far understudied. This study describes the outcome evaluation of an online questionnaire based on the carer's perception focusing on 62 QoL questions in 159 dogs with IE. Results showed that seizure frequency, but not seizure severity or presence of cluster seizures, was significantly associated with carer-perceived dog's QoL. Dogs receiving third-line antiepileptic drugs had a significantly lower perceived QoL than those that did not. Generalised linear mixed model analysis demonstrated that severity of the side effects sleeping more and ataxia were significantly associated with carer-perceived dog's QoL, with higher severities predicting lower QoL scores. The degree of carer acceptability of seizure frequency and severity was significantly associated with the dog's reported seizure frequency and severity. Moreover, there was a significant association between IE-related QoL changes of the dog and the carer, with reductions in perceived canine QoL scores associated with reductions in carer QoL, and vice versa. In conclusion, aspects of canine IE can affect both the carer and their dog's QoL. This has implications for the management and requires consideration when treatment options and outcomes are discussed.

Evaluation of quality of life in dogs with idiopathic epilepsy

Background

The impact of epilepsy and its treatment on the quality of life (QoL) is considered an important part of treatment supervision in human epilepsy.

Objectives

To develop a list of key questions evaluating QoL in dogs with idiopathic epilepsy (IE) and their carers.

Animals

One hundred fifty‐nine dogs with IE.

Methods

Cross‐sectional study. An online project questionnaire was developed containing 90 QoL‐associated questions that were initially allocated to 14 themes representing specific areas associated with the treatment and care of an epileptic dog. Principal component analysis was applied with the aim of refining the questionnaire to the least number of questions representing useful themes without loss of descriptive value. Carers were recruited by paper mail, primary practices, and canine epilepsy websites. Data were acquired from January to November 2011.

Results

Principal component analysis removed 54 questions, leaving 7 themes with 36 questions with a minimum Cronbach's alpha value of 0.7 indicating a good internal consistency: “Seizure severity and frequency”, “Adverse effects of antiepileptic drug (AED)”, “Restrictions on the carer's life”, “Frustrations over caring for a dog with IE”, “Carer distaste of AED adverse effects”, “Carer anxiety around the seizure event”, “Perceptions on rectal diazepam use”.

Conclusions and Clinical Importance

Principal component analysis successfully reduced the number of questions without loss in descriptive value. The remaining questions correlate well with each other in capturing valuable details about aspects of QoL and represent valuable key questions (EpiQoL) in the assessment of QoL for the carers of dogs with IE.

Common carotid intima-media thickness does not add to Framingham risk score in individuals with diabetes mellitus: the USE-IMT initiative

AIMS/HYPOTHESIS

The aim of this work was to investigate whether measurement of the mean common carotid intima-media thickness (CIMT) improves cardiovascular risk prediction in individuals with diabetes.

METHODS

We performed a subanalysis among 4,220 individuals with diabetes in a large ongoing individual participant data meta-analysis involving 56,194 subjects from 17 population-based cohorts worldwide. We first refitted the risk factors of the Framingham heart risk score on the individuals without previous cardiovascular disease (baseline model) and then expanded this model with the mean common CIMT (CIMT model). The absolute 10 year risk for developing a myocardial infarction or stroke was estimated from both models. In individuals with diabetes we compared discrimination and calibration of the two models. Reclassification of individuals with diabetes was based on allocation to another cardiovascular risk category when mean common CIMT was added.

RESULTS

During a median follow-up of 8.7 years, 684 first-time cardiovascular events occurred among the population with diabetes. The C statistic was 0.67 for the Framingham model and 0.68 for the CIMT model. The absolute 10 year risk for developing a myocardial infarction or stroke was 16% in both models. There was no net reclassification improvement with the addition of mean common CIMT (1.7%; 95% CI -1.8, 3.8). There were no differences in the results between men and women.

CONCLUSIONS/INTERPRETATION

There is no improvement in risk prediction in individuals with diabetes when measurement of the mean common CIMT is added to the Framingham risk score. Therefore, this measurement is not recommended for improving individual cardiovascular risk stratification in individuals with diabetes.

Altered splicing of the BIN1 muscle-specific exon in humans and dogs with highly progressive centronuclear myopathy

Amphiphysin 2, encoded by BIN1, is a key factor for membrane sensing and remodelling in different cell types. Homozygous BIN1 mutations in ubiquitously expressed exons are associated with autosomal recessive centronuclear myopathy (CNM), a mildly progressive muscle disorder typically showing abnormal nuclear centralization on biopsies. In addition, misregulation of BIN1 splicing partially accounts for the muscle defects in myotonic dystrophy (DM). However, the muscle-specific function of amphiphysin 2 and its pathogenicity in both muscle disorders are not well understood. In this study we identified and characterized the first mutation affecting the splicing of the muscle-specific BIN1 exon 11 in a consanguineous family with rapidly progressive and ultimately fatal centronuclear myopathy. In parallel, we discovered a mutation in the same BIN1 exon 11 acceptor splice site as the genetic cause of the canine Inherited Myopathy of Great Danes (IMGD). Analysis of RNA from patient muscle demonstrated complete skipping of exon 11 and BIN1 constructs without exon 11 were unable to promote membrane tubulation in differentiated myotubes. Comparative immunofluorescence and ultrastructural analyses of patient and canine biopsies revealed common structural defects, emphasizing the importance of amphiphysin 2 in membrane remodelling and maintenance of the skeletal muscle triad. Our data demonstrate that the alteration of the muscle-specific function of amphiphysin 2 is a common pathomechanism for centronuclear myopathy, myotonic dystrophy, and IMGD. The IMGD dog is the first faithful model for human BIN1-related CNM and represents a mammalian model available for preclinical trials of potential therapies.

The intracellular organization of muscle fibers relies on a complex membrane system important for muscle structural organization, maintenance, contraction, and resistance to stress. Amphiphysin 2, encoded by BIN1, plays a central role in membrane sensing and remodelling and is involved in intracellular membrane trafficking in different cell types. The ubiquitously expressed BIN1, altered in centronuclear myopathy (CNM) and myotonic dystrophy (DM), possesses a muscle-specific exon coding for a phosphoinositide binding domain. We identified splice mutations affecting the muscle-specific BIN1 isoform in humans and dogs presenting a clinically and histopathologically comparable highly progressive centronuclear myopathy. Our functional and ultrastructural data emphasize the importance of amphiphysin 2 in membrane remodeling and suggest that the defective maintenance of the triad structure is a primary cause for the muscle weakness. The canine Inherited Myopathy of Great Danes is the first faithful mammalian model for investigating other potential pathological mechanisms underlying centronuclear myopathy and for testing therapeutic approaches.

Clinical evaluation of cochlear hearing status in dogs using evoked otoacoustic emissions

OBJECTIVES

Evoked otoacoustic emission testing is the preferred test in human patients for sensorineural deafness screening in neonates and cochlear outer hair cell function monitoring in adults. This study evaluated evoked otoacoustic emission testing for cochlear function assessment in dogs within a clinical setting.

METHODS

Two populations of anaesthetised dogs were included. In group 1 the evoked otoacoustic emission response was compared to the brainstem auditory evoked response in 10 dogs having hearing assessment. Group 2 comprised 43 presumed normal dogs, in which the suitability of two types of evoked otoacoustic emissions, transient-evoked and distortion product otoacoustic emissions, were evaluated (brainstem auditory evoked response was not performed in this group).

RESULTS

Valid transient-evoked otoacoustic emission and distortion-product otoacoustic emission responses were successfully recorded within the clinical setting and correctly identified deaf and hearing ears. Within presumed healthy dogs, normal otoacoustic emission response was demonstrated in more than 80% of dogs using a single, short distortion-product otoacoustic emission run and in 78% of dogs with valid transient-evoked otoacoustic emission responses using a series of three repeated transient-evoked otoacoustic emission short runs.

CLINICAL SIGNIFICANCE

Transient-evoked otoacoustic emission and distortion-product otoacoustic emission testing provided a rapid, non-invasive frequency-specific assessment of cochlear function. Transient-evoked otoacoustic emission and distortion product otoacoustic emission testing is suitable as a screening procedure to detect loss of cochlear function in dogs, although further investigation is needed.

The MoCA: well-suited screen for cognitive impairment in Parkinson disease

OBJECTIVE

To establish the diagnostic accuracy of the Montreal Cognitive Assessment (MoCA) when screening externally validated cognition in Parkinson disease (PD), by comparison with a PD-focused test (Scales for Outcomes in Parkinson disease-Cognition [SCOPA-COG]) and the standardized Mini-Mental State Examination (S-MMSE) as benchmarks.

METHODS

A convenience sample of 114 patients with idiopathic PD and 47 healthy controls was examined in a movement disorders center. The 21 patients with dementia (PD-D) were diagnosed using Movement Disorders Society criteria, externally validated by detailed independent functional and neuropsychological tests. The 21 patients with mild cognitive impairment (PD-MCI) scored 1.5 SD or more below normative data in at least 2 measures in 1 of 4 cognitive domains. Other patients had normal cognition (PD-N).

RESULTS

Primary outcomes using receiver operating characteristic (ROC) curve analyses showed that all 3 mental status tests produced excellent discrimination of PD-D from patients without dementia (area under the curve [AUC], 87%-91%) and PD-MCI from PD-N patients (AUC, 78%-90%), but the MoCA was generally better suited across both assessments. The optimal MoCA screening cutoffs were <21/30 for PD-D (sensitivity 81%; specificity 95%; negative predictive value [NPV] 92%) and <26/30 for PD-MCI (sensitivity 90%; specificity 75%; NPV 95%). Further support that the MoCA is at least equivalent to the SCOPA-COG, and superior to the S-MMSE, came from the simultaneous classification of the 3 PD patient groups (volumes under a 3-dimensional ROC surface, chance = 17%: MoCA 79%, confidence interval [CI] 70%-89%; SCOPA-COG 74%, CI 62%-86%; MMSE-Sevens item 56%, CI 44%-68%; MMSE-World item 62%, CI 50%-73%).

CONCLUSIONS

The MoCA is a suitably accurate, brief test when screening all levels of cognition in PD.

Effects of acute tryptophan depletion on neuropsychological and motor function in Parkinson's disease

Interactions between the 5-HT system and the dopaminergic system and cholinergic system may be important in determining cognitive function and motor function in Parkinson's disease (PD). Previous studies have shown effects of reducing serotonin function, by acute tryptophan depletion (ATD), on neuropsychological function. In particular, an adverse effect on verbal memory has been demonstrated. This study compared with the effects of ATD on cognitive and motor function in PD and healthy control subjects. The effects of ATD were investigated in a double-blind, placebo-controlled, counterbalanced, cross-over, randomised design in 20 patients with PD and 35 healthy controls matched for age, gender and premorbid IQ. There was a differential group effect of ATD on global cognitive function whereby the mean score on the modified mini mental state examination during ATD was lower than placebo in PD but higher in controls. There was a similar pattern of effects on verbal recognition. In a visual recognition task, ATD improved performance in the PD but not in the control group. In terms of psychomotor speed, there was also a group-specific effect with reduced latency of response during ATD in the PD group but increased latency in the control group. ATD has subtle neuropsychological effects, which differ significantly between PD and healthy control subjects. This suggests that the dopaminergic and cholinergic deficit of PD significantly modulates the effects of serotonin depletion, resulting in positive effects in some domains. Further investigation on the effects of specific serotonin antagonists may be merited in PD.

Sequential changes in gene expression profiles in breast cancers during treatment with the aromatase inhibitor, letrozole

The study aim was to identify early (within 14 days) and late changes (by 3 months) in breast cancer gene expression profiles associated with neoadjuvant therapy with letrozole. RNA from sequential tumour biopsies in 54 patients was analyzed on microarrays; changes were determined by frequency, magnitude and significance analyses. Substantially more genes were changed at 3 months (1503) than at 14 days (237). Early changed genes were associated with cell cycle (downregulation), blood vessel development and extracellular matrix (upregulation); late changes included 'cellular metabolic process', 'generation of precursor metabolites and energy' (decreased) and 'cell adhesion' 'biological adhesion' (increased). A striking difference between the early and late changes was the general location of downregulated genes-nuclear structures at 14 days and mitochondria after 3 months. These changes in gene expression profiles provide a new and important database by which to understand molecular mechanisms of letrozole in breast cancers.

The effects of acute tryptophan depletion on mood in patients with Parkinson's disease and the healthy elderly

Reduced serotonergic tone may be a compensatory adaptation to reduced dopaminergic activity in Parkinson's disease (PD) and may result in vulnerability to depression. To test this hypothesis this study examined the effects of serotonin depletion, using the technique of acute tryptophan depletion (ATD) in PD. The effects of ATD were investigated in a double-blind, placebo-controlled, counterbalanced, cross-over, randomised design, in 20 patients with PD and 32 healthy controls matched for age, gender and pre-morbid IQ. The primary outcome was change in scores on a modified Montgomery-Asberg Depression Rating Scale (MADRS). ATD resulted in a small but statistically significant increase in score on the MADRS, but there was no effect specific to the PD group. The results do not support the hypothesis that low serotonergic tone results in vulnerability to depression in PD and are in accord with an earlier study using the same technique in PD.

Variations in serum concentration of phenobarbitone in dogs receiving regular twice daily doses in relation to the times of administration

The laboratory records of 1427 client-owned dogs on chronic phenobarbitone treatment were analysed. They were divided into two groups: the 918 dogs from which blood samples were collected at the trough, that is, within two hours before the next dose of phenobarbitone, and the 509 dogs from which samples were taken during the non-trough period. There were no significant differences between the mean serum concentrations of phenobarbitone in the trough and non-trough samples from dogs receiving doses ranging from 2 mg/kg per day to more than 10 mg/kg per day. However, the higher doses of phenobarbitone were associated with progressively lower phenobarbitone concentrations in the trough group relative to the non-trough group, and this difference was significant at doses of more than 10 mg/kg per day.

Molecular and cellular insights into a distinct myopathy of Great Dane dogs

A myopathy in the Great Dane dog with characteristic pathological and molecular features is reported. Young adults present with progressive weakness and generalised muscle atrophy. To better define this condition, an investigation using histopathology, confocal microscopy, biochemistry and microarray analysis was undertaken. The skeletal muscles of affected dogs exhibited increased oxidative fibre phenotype and core fibre lesions characterised by the disruption of the sarcomeric architecture and the accumulation of mitochondrial organelles. Affected muscles displayed co-ordinated expression of genes consistent with a slow-oxidative phenotype, which was possibly a compensatory response to chronic muscle damage. There was disruption of Z-lines in affected muscles which, at the molecular level, manifested as transcriptional dysregulation of several Z-line associated genes, including alpha-actinin, myotilin, desmin, vimentin and telethonin. The pathology of this canine myopathy is distinct from that of human central core myopathies that are characterised by cores devoid of mitochondria and by the presence of myofibrillar breakdown products.

Idiopathic epilepsy in dogs: owners' perspectives on management with phenobarbitone and/or potassium bromide

OBJECTIVES

To explore seizure management from the perspective of the owners of dogs with idiopathic epilepsy.

METHODS

Questionnaires were mailed to owners of 29 dogs under management for suspected or diagnosed idiopathic epilepsy through the clinics of the Small Animal Hospital of the University of Glasgow Veterinary School, using either phenobarbitone or potassium bromide alone or in combination.

RESULTS

The postal survey had an 86 per cent response rate. Analysis of the responses demonstrated that "the dog's quality of life", "adequate seizure frequency" and "acceptable side effects of antiepileptic drugs" were the three greatest concerns for owners; 52 per cent of owners strongly agreed that the seizure management for their dog was adequate, though the seizure frequency reported varied within this group; the majority of owners did not consider the administration of medication a nuisance. However, approximately 60 per cent of owners reported that caring for an epileptic dog had an effect on the organisation of their free time, though this was not dependent on perception of seizure control. Opinions as to the value of further diagnostic procedures, in particular intracranial imaging, were significantly affected by having pet health insurance.

CLINICAL SIGNIFICANCE

From the owners' perspective, adequacy of seizure control is determined by the balance between "the dog's quality of life", "adequate seizure frequency" and "acceptable side effects of antiepileptic drugs". A frequency of less than one seizure every three months is associated with the perception by owners of adequate seizure control.

Characteristics of magnetic resonance images of granulomatous meningoencephalomyelitis in 11 dogs

The characteristics of magnetic resonance imaging (mri) of the brains and spinal cords of 11 dogs with histologically confirmed granulomatous meningoencephalomyelitis (gme) were determined. The lesions were in the brain of eight of the dogs, in the brain and spinal cord of two, and in the spinal cord alone in one dog. A single lesion was present in four of the dogs and multiple lesions were found in six. In one dog with intracranial signs, no visible lesions could be detected on mri. No meningeal enhancement was detected in T1-weighted images post-contrast, or in fluid attenuation inversion recovery (flair) images, but there were histological lesions in the meninges in nine of the dogs. The T2-weighted images and flair sequences were characterised in all cases by hyperintensity, whereas the signal intensity of the lesions on T1-weighted images was variable. After the administration of paramagnetic contrast, some of the lesions showed no enhancement, but others showed marked patterns of enhancement. The lesions in 10 of the dogs were easily identifiable by mri and the images had several unifying characteristics, but they could not be considered disease-specific.

Oestrogen receptor beta and neoadjuvant therapy with tamoxifen: prediction of response and effects of treatment

In order to elucidate the relative importance of oestrogen receptor (ER)α, ERβ and an ERβ variant (ERβ2/βcx) in the response of breast cancers to tamoxifen, tumour levels of each receptor were assessed in 36 patients before and after 3 months of neoadjuvant treatment with tamoxifen (20 mg daily). All patients were postmenopausal women presenting with large ERα-positive breast cancers. Clinical response to treatment was assessed by tumour volume changes as determined from sequential ultrasounds and pathological response by comparison of the tumour morphology before and after treatment. Of 33 cases, 23 (70%) were classified as having a clinical response and 16 (48%) as having a response pathologically. All tumours stained positively for ERα and ERβ and 15 out of 33 (45%) for ERβ2/βcx. There were no significant differences in quantitative expression of any receptor between tumours that subsequently responded and that did not, whether response was assessed clinically or pathologically. Tamoxifen treatment was associated with a decrease in ERα, but an increase was the most frequent change (17 out of 33) in ERβ, and no consistent change was evident in staining of the ERβ2/βcx variant. In summary, ERβ1 and ERβ2/βcx variant protein are detected in ERα-positive breast tumours but their expression is not associated with a response to tamoxifen. Differential changes in ERα and ERβ were seen with treatment.

Proliferation, steroid receptors and clinical/pathological response in breast cancer treated with letrozole

Sixty-three postmenopausal women with large primary breast cancers were treated with neoadjuvant letrozole (2.5 mg daily) for 3 months. Tumour samples were taken at diagnosis and after 10–14 days and 3 months treatment. Immunohistochemical staining for Ki67, oestrogen receptor (ER) and progesterone receptor (PgR) was performed and related to clinical (ClinR) and pathological responses (PathR) after 3 months treatment. ClinR was observed in 48 of 63 cases (76.2%) and PathR in 47 of 62 (75.8%). Pretreatment Ki67 scores were similar in responders (R) and non-responders (NR). Highly significant Ki67 decreases occurred in all tumour subgroups at 10–14 days (P<0.005). A significant difference in Ki67 scores at 10–14 days (P<0.007) was found between PathR and PathNR but not between ClinR and ClinNR. At 3 months, decreases from pretreatment Ki67 scores were highly significant in all tumour subgroups irrespective of response status. However, whereas Ki67 scores were significantly different between pathological R and NR (P=0.009), the corresponding comparison of ClinR status was not. Significant decreases between 10–14 days and 3 months were found only in ClinR and PathR (P=0.02 and 0.045, respectively). Treatment significantly reduced PgR expression at 14 days and 3 months (both P<0.0001), but the level of changes was not different between response status groups. In summary, letrozole produces rapid and profound decreases in expression of Ki67 and PgR but changes do not always correlate with clinical and pathological responses.

Inherited myopathy of great Danes

A hereditary, non-inflammatory myopathy occurring in young great Danes with distinctive histological features in muscle biopsy specimens is reviewed. Onset of clinical signs is usually before one year of age and both sexes are affected. Clinical signs are characterised by exercise intolerance, muscle wasting, and an exercise-induced tremor. Although most affected dogs have a severe form of the disease, occasional dogs may have a less pronounced form and survive into adulthood with an acceptable quality of life. Litters containing affected puppies are born to clinically unaffected parents, and an autosomal recessive pattern of inheritance is likely. All recorded cases have had fawn or brindle coat coloration. Elevated serum creatinine kinase concentrations and spontaneous electrical activity in skeletal muscles are frequently found. While originally reported (Targett and others 1994) as a central core myopathy in this breed, the histochemical characteristics of the distinct cytoarchitectural structures differ from those of the well-characterised central core myopathy in human beings. In fact, these structures differ from any known myopathy in human beings and likely represents a unique non-inflammatory myopathy affecting dogs. Until this myopathy is characterised further, the name inherited myopathy in great Danes is suggested.

Growth factor signalling in clinical breast cancer and its impact on response to conventional therapies: the Edinburgh experience

Neoadjuvant endocrine treatment in which therapy is given while the primary tumour is still in the breast provides a highly useful model system by which to identify mechanisms associated with de novo resistance and signs of early acquired resistance. Most importantly, the model is clinically relevant. It has been confirmed that the absence of tumour oestrogen receptors confers resistance to endocrine therapy. Early changes in tumour cell proliferation following neoadjuvant treatment with the third-generation aromatase inhibitor, letrozole, do not predict accurately for subsequent clinical response. Additionally, changes in proliferation seen at later times can be the consequence of response and may be associated with early resistance. High expression of c-erbB2 does not reduce tumour responses to neoadjuvant treatment with aromatase inhibitors, but is associated with high tumour proliferation before and during treatment. It remains to be determined whether these characteristics confer subsequent resistance to treatment and early relapse in the adjuvant setting.

Aromatase inhibitors: cellular and molecular effects

Marked cellular and molecular changes may occur in breast cancers following treatment of postmenopausal breast cancer patients with aromatase inhibitors. Neoadjuvant protocols, in which treatment is given with the primary tumour still within the breast, are particularly illuminating. In Edinburgh, we have shown that 3 months treatment with either anastrozole, exemestane or letrozole produces pathological responses in the majority of oestrogen receptor (ER)-rich tumours (39/59) as manifested by reduced cellularity/increased fibrosis. Changes in histological grading may also take place, most notably a reduction in mitotic figures. This probably reflects an influence on proliferation as most tumours (82%) show a marked decrease in the proliferation marker, Ki67. These effects are generally more dramatic than seen with tamoxifen given in the same setting. Differences between aromatase inhibitors and tamoxifen are also apparent in changes in steroid hormone expression. Thus, immuno-staining for progesterone receptor (PgR) is reduced in almost all cases by aromatase inhibitors, becoming undetectable in many. This contrasts with effects of tamoxifen in which the most common change on PgR is to increase expression. Changes in proliferation occur rapidly following the onset of exposure to aromatase inhibitors. Thus, neoadjuvant studies with letrozole in which tumour was sampled before and after 14 days and 3 months treatment show that decreased expression of Ki67 occur at 14 days and, in many cases, the effect is greater at 14 days than 3 months. These early changes precede evidence of clinical response but do not predict for it. However, this study design has allowed RNA analysis of sequential biopsies taken during the neoadjuvant therapy. Based on clustering techniques, it has been possible to subdivide tumours into groups showing distinct patterns of molecular changes. These changes in tumour gene expression may allow definition of tumour cohorts with differing sensitivity to aromatase inhibitors and permit early recognition of response and resistance.

The validation of new aromatase monoclonal antibodies for immunohistochemistry--a correlation with biochemical activities in 46 cases of breast cancer

Intratumoral aromatase is a therapeutic target for the treatment of post-menopausal estrogen-dependent breast cancers. Therefore, reliable methods should be developed for routine application for the detection of intratumoral aromatase. Immunohistochemistry (IHC) is considered one of the most suitable methods in this regard. A multi-centre collaborative group has been established to generate and validate new aromatase monoclonal antibodies. We have selected two monoclonal antibodies, #677 against native aromatase protein and F2 against formalin-fixed protein for this purpose. With these two monoclonal antibodies 43 cases of invasive ductal carcinoma, which had been previously assayed for aromatase activity by product isolation methodology, were immunostained in three laboratories in UK, USA and Japan and independently evaluated by three pathologists (H.S., T.A. and S.G.S.). Staining of malignant epithelium, adipose tissue, normal/benign and stromal compartments of the tumors were assessed by estimating the proportion of positive staining cells and the relative intensity of staining in this fashion. Immunoreactivity could be detected in each component of the tissue specimens but a significant positive correlation with biochemical activity was detected only in malignant epithelium stained with 677 not in other components with #677 and not in any of the components. Staining using F2 as a primary antibody did not produce a positive correlation in any components with aromatase activity. These results suggest that we now have a monoclonal antibody against aromatase (#677) which may be used to stain archival materials. A methodology and scoring system is recommended whereby staining significantly correlates with aromatase activity of the resected tissue specimens of breast cancer.

Randomised controlled trial of mammographic screening in women from age 40: predicted mortality based on surrogate outcome measures

A trial in the UK to study the effect on mortality from breast cancer of invitation for annual mammography from the age of 40–41, has randomised a total of 160 921 women in the ratio 1 : 2 to the intervention and control arms. All breast cancers diagnosed in the two arms have been identified, and the histology reviewed. This paper presents the results of an interim analysis using surrogate outcome measures to compare predicted breast cancer mortality in the two arms based on 1287 cases diagnosed to 31.12.1999. Due to earlier diagnosis, there is currently an 8% excess of invasive breast cancers in the intervention arm. The ratio of predicted deaths at 10 years in the intervention arm relative to the control arm, adjusted for this excess diagnosis, ranges from 0.89 (95% confidence interval (CI) 0.78–1.01) to 0.90 (95% CI 0.80–1.01). Screening from age 40 may result in a lower reduction in breast cancer mortality than that observed in other trials including women below age 50. This analysis based on surrogate outcome measures suggests that a reduction in breast cancer mortality may be observed in this trial. However, a number of assumptions have been necessary and firm conclusions must await the analysis of observed mortality from breast cancer.

Reversible posterior leukoencephalopathy syndrome: a misnomer reviewed

Reversible posterior leukoencephalopathy is a syndrome of headache, seizures and visual loss, often associated with an abrupt increase in blood pressure. Prompt diagnosis and therapy with antihypertensives, anticonvulsants, removal of any offending medication and treatment of associated disorders is essential since early treatment might prevent progression to irreversible brain damage. We present six illustrative cases presenting to Christchurch Hospital and review the condition. All were hypertensive, two were receiving immunosuppressant therapy after transplantation and one chemotherapy. Only three made a full recovery. The term reversible posterior leukoencephalopathy is a misnomer as the condition is not always reversible, is not necessarily confined to the posterior regions of the brain and can affect both white and grey matter. Magnetic resonance imaging findings of increased T2 and fluid attenuated inversion recovery signal predominantly involving the posterior regions of the cerebral hemispheres should alert the clinician to the possibility of this diagnosis.

Anastrozole demonstrates clinical and biological effectiveness in oestrogen receptor-positive breast cancers, irrespective of the erbB2 status

Overexpression of erbB2 in breast tumours can predict resistance to tamoxifen therapy. We conducted a small trial to determine if erbB2 status correlates with tumour response and biochemical changes in postmenopausal women receiving neoadjuvant therapy with the aromatase inhibitor, anastrozole. Twenty-four postmenopausal women with oestrogen receptor (ER)-rich, large, operable breast tumours received three months of neoadjuvant anastrozole, 1 or 10 mg daily, then surgery, followed by another five years of anastrozole 1 mg daily. Response to the treatment was based on changes in clinical and ultrasound measurements of tumour volume and changes in tumour proliferation and progesterone receptor (PgR) status. After follow-up for a median duration of four years therapy, there was no apparent difference between erbB2 0/1+ and erbB2 3+ tumours in clinical response or changes in proliferation and PgR expression. In conclusion, anastrozole appears to be an effective endocrine option in this patient population, irrespective of the erbB2 status.

Suspected pituitary apoplexy in a German shorthaired pointer

Pituitary apoplexy is a syndrome which has been described in humans caused by acute haemorrhage or infarction within a pituitary tumour or a non-tumorous pituitary gland. This report describes the authors' observations of a dog in which vomiting, visual disturbances, seizures, altered consciousness and diencephalic dysfunction occurred in association with haemorrhage originating from a pituitary macroadenoma. The clinical signs were thought to be consistent with disruption of the hypothalamus and brainstem, together with raised intracranial pressure due to intraventricular haemorrhage. These signs, and the pathological findings, bear a striking resemblance to those associated with the syndrome of pituitary apoplexy, seen in humans.

Measures of benefit for breast screening from the pathology database for Scotland, 1991-2001

AIMS

To examine pathology characteristics of breast cancers detected by mammography screening over 10 years in Scotland, and compare the nature of cancer yields after different levels of very small invasive cancer at prevalence detection.

METHODS

A pathology database of cancers from mammography screening of women aged 50-64 years invited every three years was used to assess the variation over time in annual yield of different invasive cancer sizes. Screening centres were compared for incidence screen yields, according to sizes, histological type, grade, and node status.

RESULTS

There was a significant trend over time for increased detection of < 15 mm cancers among 2353 prevalence cancers, and a significant trend for increase in all size groups, < 10, 10-14, < 15, and >or= 15 mm, among 2245 incidence cancers. Based on individual screening centres, there was a significant negative relation between proportions of very small (< 10 mm) cancers at prevalence screens and of large (>or= 15 mm) cancers at incidence screens of the same "cohort" three years later. There was no significant relation on the same centre basis for worse pathology characteristics (histological no special type, high grade, and positive node status) in cancers detected in the same "cohort" three years later.

CONCLUSIONS

Sensitive mammography screening has a significant effect on the nature of yields at subsequent screens. Length of screening interval and consistency in pathologist opinions are factors that account for lack of effect on incidence cancer qualitative pathology characteristics. These issues are relevant to the use of such characteristics as surrogate measures of service screening performance.

Validation of new aromatase monoclonal antibodies for immunohistochemistry: progress report

Intratumoral aromatase is a potential therapeutic target for the treatment of postmenopausal estrogen-dependent breast cancers. Therefore, reliable methods should be developed for routine application for the detection of intratumoral aromatase. A multi-center collaborative group has been established to generate and validate new aromatase monoclonal antibodies (MAbs). A recombinant GST-aromatase fusion protein was expressed in baculovirus and the purified protein was used for immunization of mice either as a native or formalin-fixed antigen. Hybridomas were generated using standard techniques and screened biochemically prior to immunohistochemistry (IHC) evaluation in human placenta, ovary and breast cancer tissues. Twenty-three MAbs selected by biochemical assays were further evaluated by IHC of paraffin-embedded tissue sections including normal ovary, and placenta, and a small series of 10 breast carcinomas. Of the 23 MAbs, 2 (clones 677 and F2) were determined to specifically stain cell types known to express aromatase in normal tissues. In breast carcinomas staining of malignant epithelium, adipose tissue, normal/benign and stromal compartments was detected. IHC was performed and independently evaluated by three pathologists (HS, TJA and SGS), each using the same evaluation criteria for staining intensity and proportion of immunopositive cells. With these two MAbs, interpathologist and intralaboratory variations were minimal in comparison with differences which could be detected between tissue specimens and antibodies.

An integrated view of aromatase and its inhibition

Aromatase inhibition has become a major treatment strategy for postmenopausal women with oestrogen-dependent breast cancer. Its optimal application is, however, dependent upon (i) the accurate identification of cancers which are ultimately dependent upon the activity of the aromatase enzyme, (ii) the use of the best method/inhibitor by which to blockade aromatase activity. The single best predictor of response to aromatase inhibitors is the presence of tumour oestrogen receptors; receptor-negative cancers rarely respond whereas those with high levels seem particularly likely to benefit. However, there is a need for additional discriminatory markers. The use of microarray technology coupled with neoadjuvant therapy is likely to yield promising candidate genes. The finding that, amongst peripheral tissues, the tumour itself may have high activity has led to the suggestion that the tumour aromatase measurements may be predictive; however, in situ studies and the lack of robust assays for tumour aromatase suggest that tumour aromatase may not be an influential marker. Whilst drugs such as anastrozole, exemestane, formestane and letrozole are all effective and specific inhibitors of aromatase, they differ in structure, potency and mechanism of action. Thus, differential sensitivity of tissues/tumours and non-cross resistance mean inhibitors are not equivalent and individual agents may have differing roles according to the setting in which they will be used. Aromatase inhibitors have evolved as key endocrine agents in the treatment of breast cancer. They offer the promise of rational treatment management based on the accurate identification of individual cohorts of tumours responsive to specific drugs.

EMMA--an eye movement measurement and analysis system

A system has been developed for stimulation, recording and analysis of a wide range of eye movements. Eye movements are stimulated with an LED bar or a video projector under the control of a PC. The eye movements are measured using a scleral reflection technique (IRIS instrument), and sampled and stored on a PC. A range of tests have been developed to measure saccadic and smooth pursuit eye movements. A variety of tools have been developed to assist in the analysis of the data. Several research studies have ably demonstrated the utility and versatility of the system.

Pathological features of breast cancer response following neoadjuvant treatment with either letrozole or tamoxifen

Morphological characteristics, grading features, proliferation marker MIB1, apoptosis (by Tdt-mediated duTP-biotin nick-end labelling (TUNEL)), Bcl-2 expression, oestrogen receptor (ER) and progesterone receptor (PgR) status were compared in ER-positive breast cancers before and after 3 months of neoadjuvant therapy with either letrozole or tamoxifen. Daily treatment was with letrozole 2.5 mg (12 patients) or 10 mg (12 patients), or with tamoxifen 20 mg(24 patients). Letrozole treatment was associated with a pathological response in 17 of 24 (71%) patients. The predominant change in grading features was a decrease in mitosis, and the expression of MIB1 was reduced in all of the 22 evaluable cases. Whilst only marginal changes were observed in ER expression following letrozole therapy, PgR reactivity was reduced in 20 of 21 evaluable cases which were initially PgR-positive, becoming undetectable in 16 patients. Tamoxifen treatment was associated with pathological response in 15 of 24 (63%) tumours. In contrast to letrozole, the dominant change in grading feature was an increase in tubule formation, ER score was markedly reduced in most cases, and the most common effect on PgR was an increased expression. Following treatment with either tamoxifen or letrozole, variable effects were observed on the apoptotic index and expression of Bcl-2. These results indicate that both letrozole and tamoxifen have marked influences on the pathological features of breast cancer during neoadjuvant therapy. However, the effects of the two agents varied such that the phenotypes of letrozole- and tamoxifen-treated tumours differ markedly. Effects on clinical, pathological and biological endpoints were frequently disconcordant--future studies will therefore require the evaluation of multiple parameters in order to fully assess tumour response.

Saccade sequences as markers for cerebral dysfunction following mild closed head injury

Diffuse axonal injury caused by mild closed head injury (CHI) is likely to affect the neural networks concerned with the planning and execution of sequences of memory-guided saccades. Thirty subjects with mild CHI and thirty controls were tested on 2- and 3-step sequences of memory-guided saccades. CHI subjects showed more directional errors, larger position errors, and hypermetria of primary saccades and final eye position. No deficits were seen in temporal accuracy (timing and rhythm). These results suggest that computerized tests of saccade sequences can provide sensitive markers of cerebral dysfunction after mild CHI.

Anti-tumor effects of letrozole

The use of drugs, which inhibit estrogen biosynthesis, is an attractive treatment for postmenopausal women with hormone-dependent breast cancer. Estrogen deprivation is most specifically achieved using inhibitors which block the last stage in the biosynthetic sequence, i.e., the conversion of androgens to estrogens by the aromatase enzyme. Recently, a new generation of aromatase inhibitors has been developed. Among these, letrozole (Femara) appears to be the most potent. When given orally in milligram amounts per day to postmenopausal women, the drug almost totally inhibits peripheral aromatase and causes a marked reduction in circulating estrogens to levels that are often undetectable in conventional assays. Similarly, neoadjuvant studies demonstrate that letrozole substantially inhibits aromatase activity in both malignant and nonmalignant breast tissues, and markedly suppresses endogenous estrogens within the breast cancers. These studies also illustrate anti-estrogenic and anti-proliferative effects of letrozole in estrogen receptor (ER)-rich tumors. Thus, tumor expression of progesterone receptors and the cell-cycle marker Ki67 is significantly and consistently reduced with treatment. Additionally, clear pathological responses as evidenced by decreased cellularity and increased fibrosis are seen in the majority of cases. These results translated into clinical benefit in a series of 24 breast cancers treated neoadjuvantly with letrozole (either 2.5 or 10 mg): tumor volume reductions > 25% were observed in 23 women, and > 50% reductions in 18 patients. Pathological and clinical effects are seen much more consistently than with tamoxifen. Thus, in a multicenter randomized trial of letrozole vs. tamoxifen (PE 024), clinical study outcomes were superior for letrozole in comparison with tamoxifen with regard to overall tumor response and an increase in the proportion of patients treated by breast conserving surgery. Letrozole has also been used in advanced breast cancer, both as second-line hormone treatment following tamoxifen failure, and more recently as first-line therapy. Trials of second-line treatment in which letrozole has been compared with either older aromatase inhibitors or progestins have shown equivalent or superior clinical activity and improved tolerability favoring letrozole. In first-line comparison with tamoxifen in metastatic disease, a phase III trial of over 900 postmenopausal women showed letrozole to be significantly better than tamoxifen in terms of overall tumor response rates, clinical benefit, and time to treatment failure. In summary, letrozole is an exceptionally potent and specific endocrine agent. In patients with ER-rich tumors, high rates of pathological and clinical response have been documented, and large phase III trials against established treatments such as tamoxifen and progestin suggest superior (or at least equivalent) clinical efficacy. Letrozole is a drug of immense potential and in the future is likely to occupy a central role in the management of postmenopausal women with hormone-dependent breast cancer.

Neoadjuvant endocrine therapy of breast cancer: a surgical perspective

Neoadjuvant treatment with chemotherapy or endocrine agents is being used increasingly to downstage locally advanced and large operable breast cancers. Following these treatments, inoperable breast cancer often becomes fully resectable, and initially operable tumours requiring mastectomy may be successfully removed by breast-conserving surgery. Patient selection is important to optimise neoadjuvant endocrine therapy: only patients with oestrogen receptor (ER)-rich breast cancer are candidates, and postmenopausal women are likely to benefit the most. Such patients can expect a high probability of responses over a 3-month treatment period. Response to therapy should be monitored by clinical examination as well as by ultrasound, mammography, or other imaging procedures. Third-generation aromatase inhibitors (letrozole, anastrozole and exemestane) are more effective than tamoxifen in this treatment setting. In a large randomised trial of neoadjuvant endocrine therapy in postmenopausal women, letrozole achieved significantly higher response rates than tamoxifen, and a correspondingly higher rate of breast-conserving surgery was possible in the letrozole-treated patients. There is some evidence to suggest that the nature of the tumour response is different for preoperative endocrine therapy compared with chemotherapy. This difference may result in a higher rate of complete tumour excisions following breast-conserving surgery after neoadjuvant endocrine treatment. There appears to be a low rate of subsequent local recurrence in patients having breast-conserving therapy after neoadjuvant endocrine therapy.

Survival of, and competition between, oligodendrocytes expressing different alleles of the Plp gene

Mutations in the X-linked Plp gene lead to dysmyelinating phenotypes and oligodendrocyte cell death. Here, we exploit the X inactivation phenomenon to show that a hierarchy exists in the influence of different mutant Plp alleles on oligodendrocyte survival. We used compound heterozygote mice to study the long-term fate of oligodendrocytes expressing either the jimpy or rumpshaker allele against a background of cells expressing a Plp-null allele. Although mutant and null oligodendrocytes were generated in equal numbers, the proportion expressing the mutant allele subsequently declined, but whereas those expressing the rumpshaker allele formed a reduced but stable population, the number of jimpy cells fell progressively. The age of decline in the jimpy cells in different regions of the CNS correlated with the temporal sequence of myelination. In compound heterozygotes expressing rumpshaker and jimpy alleles, oligodendrocytes expressing the former predominated and were more abundant than when the rumpshaker and null alleles were in competition. Thus, oligodendrocyte survival is not determined solely by cell intrinsic factors, such as the conformation of the misfolded PLP, but is influenced by neighboring cells, possibly competing for cell survival factors.

Effect of neoadjuvant treatment with anastrozole on tumour histology in postmenopausal women with large operable breast cancer

Anastrozole is an orally active, non-steroidal aromatase inhibitor which appears effective as neoadjuvant treatment of breast cancer. Histological changes have been evaluated in biopsies from large, oestrogen-receptor rich, operable breast tumours in postmenopausal women following 12 weeks of neoadjuvant anastrozole treatment (1 mg (n=12) or 10 mg (n=11)). Of the 23 patients, 18 had a clinical response following treatment. Compared with pre-treatment biopsies anastrozole-treated specimens displayed decreased cellularity and/or increased fibrosis in 15 tumours; changes in gland formation, nuclear pleomorphism, or mitoses, in 12 cases; and a reduction in Mib1 score in all tumours. Marked changes in apoptotic scores were seen following treatment but the direction of effect was inconsistent. In all 17 tumours which were positive for progesterone receptors before therapy, treatment was associated with reduced staining for progesterone receptors. There was no consistent effect of treatment on oestrogen-receptor expression. It is concluded that neoadjuvant anastrozole treatment in this patient group has marked effects on tumour histopathology but these do not always correlate with clinical response.

Persistence of a vancomycin-resistant Enterococcus faecium in an anaerobic continuous-flow culture of porcine microflora in the presence of subtherapeutic concentrations of vancomycin

Recombined porcine continuous-flow culture (RPCF) maintained in a continuous-flow fermentation system is effective in protecting neonatal and weaned pigs against infection by enteropathogens. In the current study, we demonstrate the effect of RPCF on vancomycin-resistant enterococci (VRE) in the presence and absence of subtherapeutic levels of vancomycin. Also examined was the ability of VRE to transfer vancomycin resistance to endogenous Enterococcus faecalis 137.1. When RPCF was challenged with VRE, the rate of VRE clearance was dependent on the method of challenge. In the control experiment, RPCF was challenged with 7.0 log10/CFU/ml VRE. Clearance of VRE from the culture was observed within 7 days at a rate of 1.44 log10/day. RPCF containing 0.001 microg/ml vancomycin cleared VRE at a slightly lower rate of 0.94 log10/day. RPCF containing 0.01 microg/ml or 0.1 microg/ml vancomycin reduced the level of VRE from 7.0 log10/CFU/ml to 2.0 log10/CFU/ml within 9 days, but failed to clear the VRE after 24 days. During the period of decline, the VRE clearance rate for the 0.01 microg/ml and 0.1 microg/ml vancomycin-treated cultures was 0.52 log10/day, and 0.53 log10/day, respectively. E. faecalis 137.1 endogenous to RPCF did not acquire the vancomycin resistance genes throughout the experiment as evidenced by direct selection, ribotyping, and pulsed-field gel electrophoresis.

Occult lymph node metastases in patients with ‘node negative’ breast carcinoma treated with conservation surgery and axillary node sample and who subsequently developed axillary recurrence

We examined axillary lymph nodes from 26 patients with node-negative breast cancer managed by axillary node sampling and no further axillary treatment, but who subsequently developed axillary recurrence after a mean follow-up of 7 years to determine the incidence of micrometastatic disease in these patients. Twenty-six matched controls with an identical length of follow-up who were node-negative on an axillary node sample, but have not developed axillary recurrence, also underwent node examination and the incidence of metastases in the two groups were compared. Lymph nodes were sectioned at two additional levels 100 microm apart. Sections at each level were stained with haematoxylin and eosin (H&E) and antibodies to PanCK and MUC1 protein. The original H&E section from each node was reviewed and additional sections from each lymph node were examined by a pathologist who was blinded to outcome. Review of the original H&E sections of the nodes revealed metastases that had been overlooked at the time of diagnosis in two (8%) patients from the recurrence group. A further two (8%) patients from the recurrence group and three (12%) from the control group had axillary nodes which contained micrometastases. Immunocytochemistry was important in identifying all micrometastases. There was no significant difference in the incidence of axillary node micrometastases between patients with and without axillary node recurrence. Although the number of cases was small, this study suggests that axillary recurrence following a negative sampling procedure is not commonly due to missed axillary node metastases.

MIB-1 Assessments in breast cancers

The variability of MIB-1 measurements in breast cancer was assessed in histological sections from core and excision biopsies taken simultaneously in 13 cases and sequentially (with an intervening period of 2-3 weeks) in 17 cases. Results showed no significant differences in values between cores and sections, whether taken simultaneously or sequentially. Individual pairs of cores and sections occasionally demonstrated substantial differences. The mean ratio of MIB-1 scores between cores and sections was 0.97 [95% confidence interval (CI)=0.68-1.38]. However 95% confidence intervals for ratios within individuals were 0.14-6.68. Although the two samples can be equivalent on an average over numerous patients, they cannot be taken as equivalent within individuals. Severe heterogeneity complicates the assessment of MIB-1 in individual breast cancers and limits utility in monitoring changes in proliferation with treatment.

Sodium chlorate supplementation reduces E. coli O157:H7 populations in cattle

Cattle are a natural reservoir of the food-borne pathogen Escherichia coli O157:H7. Therefore, strategies that reduce E. coli O157:H7 prior to slaughter will reduce human exposures to this virulent pathogen. When bacteria that can anaerobically respire on nitrate (e.g., E. coli) are exposed to chlorate, they die because the intracellular enzyme nitrate reductase converts nitrate to nitrite, but also co-metabolically reduces chlorate to cytotoxic chlorite. Because chlorate is bactericidal only against nitrate reductase-positive bacteria, it has been suggested that chlorate supplementation be used as a strategy to reduce E. coli O157:H7 populations in cattle prior to harvest. Cattle (n = 8) were fed a feedlot-style high-grain diet experimentally infected with three strains of E. coli O157:H7. Cattle were given access to drinking water supplemented with 2.5 mM KNO3 and 100 mM NaCl (controls; n = 4) or 2.5 mM KNO3 and 100 mM NaClO3 (chlorate-treated; n = 4). Sodium chlorate treatment for 24 h reduced the population of all E. coli O157:H7 strains approximately two logs (10(4) to 10(2)) in the rumen and three logs (10(6) to 10(3)) in the feces. Chlorate treatment reduced total coliforms and generic E. coli from 106 to 10(4) in the rumen and by two logs throughout the rest of the gastrointestinal tract (ileum, cecum, colon, and rectum). Chlorate treatment reduced E. coli O157:H7 counts throughout the intestinal tract but did not alter total culturable anaerobic bacterial counts or the ruminal fermentation pattern. Therefore, it appears that chlorate supplementation is a viable potential strategy to reduce E. coli O157:H7 populations in cattle prior to harvest.