Diffusion-weighted magnetic resonance imaging for diagnosis of post-operative paediatric cholesteatoma.

OBJECTIVES: High rates of recidivism are reported after paediatric cholesteatoma surgery. Our practice has adapted to include non-echoplanar diffusion-weighted magnetic resonance imaging for the diagnosis of residual or recurrent cholesteatoma. This audit aimed to evaluate the performance of non-echoplanar diffusion-weighted magnetic resonance imaging in our paediatric population. METHODS: A retrospective review was conducted of non-echoplanar diffusion-weighted magnetic resonance imaging scans performed to detect residual disease or recurrence after surgery for cholesteatoma in children from 1 January 2012 to 30 November 2017 in our centre. Follow-up diffusion-weighted magnetic resonance imaging scans were reviewed to 16 August 2019. RESULTS: Thirty-four diffusion-weighted magnetic resonance imaging scans were included. The sensitivity and specificity values of diffusion-weighted magnetic resonance imaging for detecting post-operative cholesteatoma were 81 per cent and 72 per cent, respectively. Positive predictive and negative predictive values were 72 per cent and 81 per cent, respectively. CONCLUSION: Use of diffusion-weighted magnetic resonance imaging is recommended as a replacement for routine second-look surgical procedures in the paediatric population. However, we would caution that patients require close follow up after negative diffusion-weighted magnetic resonance imaging findings.

Rapid and fully automated bacterial pathogen detection on a centrifugal-microfluidic LabDisk using highly sensitive nested PCR with integrated sample preparation.

Diagnosis of infectious diseases suffers from long turnaround times for gold standard culture-based identification of bacterial pathogens, therefore impeding timely specific antimicrobial treatment based on laboratory evidence. Rapid molecular diagnostics-based technologies enable detection of microorganisms within hours however cumbersome workflows and complex equipment still prevent their widespread use in the routine clinical microbiology setting. We developed a centrifugal-microfluidic "LabDisk" system for rapid and highly-sensitive pathogen detection on a point-of-care analyser. The unit-use LabDisk with pre-stored reagents features fully automated and integrated DNA extraction, consensus multiplex PCR pre-amplification and geometrically-multiplexed species-specific real-time PCR. Processing merely requires loading of the sample and DNA extraction reagents with minimal hands-on time of approximately 5 min. We demonstrate detection of as few as 3 colony-forming-units (cfu) of Staphylococcus warneri, 200 cfu of Streptococcus agalactiae, 5 cfu of Escherichia coli and 2 cfu of Haemophilus influenzae in a 200 µL serum sample. The turnaround time of the complete analysis from "sample-to-result" was 3 h and 45 min. The LabDisk consequently provides an easy-to-use molecular diagnostic platform for rapid and highly-sensitive detection of bacterial pathogens without requiring major hands-on time and complex laboratory instrumentation.

Comparing the effects of subchronic phencyclidine and medial prefrontal cortex dysfunction on cognitive tests relevant to schizophrenia.

RATIONALE: It is becoming increasingly clear that the development of treatments for cognitive symptoms of schizophrenia requires urgent attention, and that valid animal models of relevant impairments are required. With subchronic psychotomimetic agent phencyclidine (scPCP), a putative model of such impairment, the extent to which changes following scPCP do or do not resemble those following dysfunction of the prefrontal cortex is of importance. OBJECTIVES: The present study carried out a comparison of the most common scPCP dosing regimen with excitotoxin-induced medial prefrontal cortex (mPFC) dysfunction in rats, across several cognitive tests relevant to schizophrenia. METHODS: ScPCP subjects were dosed intraperitoneal with 5 mg/kg PCP or vehicle twice daily for 1 week followed by 1 week washout prior to behavioural testing. mPFC dysfunction was induced via fibre-sparing excitotoxin infused into the pre-limbic and infralimbic cortex. Subjects were tested on spontaneous novel object recognition, touchscreen object-location paired-associates learning and touchscreen reversal learning. RESULTS: A double-dissociation was observed between object-location paired-associates learning and object recognition: mPFC dysfunction impaired acquisition of the object-location task but not spontaneous novel object recognition, while scPCP impaired spontaneous novel object recognition but not object-location associative learning. Both scPCP and mPFC dysfunction resulted in a similar facilitation of reversal learning. CONCLUSIONS: The pattern of impairment following scPCP raises questions around its efficacy as a model of cognitive impairment in schizophrenia, particularly if importance is placed on faithfully replicating the effects of mPFC dysfunction.

In vivo interactions between ionizing radiation, inflammation and chemical carcinogens identified by increased DNA damage responses.

Exposure to ionizing radiation or a variety of chemical agents is known to increase the risk of developing malignancy and many tumors have been linked to inflammatory processes. In most studies, the potentially harmful effects of ionizing radiation or other agents are considered in isolation, mainly due to the large number of experiments required to assess the effects of mixed exposures with different doses and different schedules, and the length of time and expense of studies using disease as the measure of outcome. Here, we have used short-term DNA damage responses to identify interactive effects of mixed exposures. The data demonstrate that exposure to ionizing radiation on two separate occasions ten days apart leads to an increase in the percentage of cells with a sub-G(0) DNA content compared to cells exposed only once, and this is a greater than additive effect. Short-term measurements of p53 stabilization, induction of p21/Cdkn1a and of apoptosis also identify these interactive effects. We also demonstrate similar interactive effects of radiation with the mutagenic chemical methyl-nitrosourea and with a nonspecific pro-inflammatory agent, lipopolysaccharide. The magnitude of the interactive effects is greater in cells taken from mice first exposed as juveniles compared to adults. These data indicate that short-term measurements of DNA damage and response to damage are useful for the identification of interactions between ionizing radiation and other agents.

New translational assays for preclinical modelling of cognition in schizophrenia: the touchscreen testing method for mice and rats.

We describe a touchscreen method that satisfies a proposed 'wish-list' of desirables for a cognitive testing method for assessing rodent models of schizophrenia. A number of tests relevant to schizophrenia research are described which are currently being developed and validated using this method. These tests can be used to study reward learning, memory, perceptual discrimination, object-place associative learning, attention, impulsivity, compulsivity, extinction, simple Pavlovian conditioning, and other constructs. The tests can be deployed using a 'flexible battery' approach to establish a cognitive profile for a particular mouse or rat model. We have found these tests to be capable of detecting not just impairments in function, but enhancements as well, which is essential for testing putative cognitive therapies. New tests are being continuously developed, many of which may prove particularly valuable for schizophrenia research.

Readability and content of postoperative tonsillectomy instructions given to patients in Scotland, a completed audit cycle.

The aim of this study was to assess the impact of the recommendations and interventions of the 2003 audit of 'readability and content of postoperative tonsillectomy instructions, given to patients in Scotland'. A two-cycle audit of readability and content of postoperative tonsillectomy instructions was undertaken. All National Health Service (NHS) hospital wards and associated Otolaryngology Departments in Scotland where tonsillectomies were being performed were contacted. Interventions following the first cycle included the mailing copies of original audit results and conclusions to all ear, nose and throat wards in Scotland, presentation at a National Meeting and publication of results in a peer reviewed journal. While changes had occurred in 61% of the information sheets, and with six of the 31 (19%) postoperative information sheets now being written at or below the recommended reading level, the average reading grade/age required to understand these information sheets still remains above those recommended by patient education experts. In conclusion, the majority of postoperative tonsillectomy information sheets in Scotland remain written at a level above those recommended by patient education experts. The interventions undertaken in this audit were of limited success. The ENT-UK Tonsillectomy Information sheets (2006) are written at reasonable reading levels, have good content levels and we continue to recommend these information sheets.

Diagnosis of tuberculosis in the head and neck.

OBJECTIVES: To establish the features of Mycobacterium tuberculosis infection in the head and neck region, and to determine which investigations have the greatest diagnostic accuracy. STUDY DESIGN: Region-based, retrospective cohort study. METHOD: The study included 148 patients with tuberculosis of the head and neck treated in the Greater Glasgow and Clyde region between 2000 and 2007. RESULTS: The following diagnostic sensitivities were calculated: 53 per cent for fine needle aspiration, 95 per cent for core biopsy and 91 per cent for lymph node excision biopsy. There was a statistically significant difference between the sensitivity results for fine needle aspiration versus core biopsy (p = 0.0003) and fine needle aspiration versus excision biopsy (p < 0.0001). There was no statistically significant difference between the sensitivity results for core biopsy and excision biopsy. CONCLUSION: Core biopsy has equivalent diagnostic accuracy to excision biopsy in the investigation of head and neck tuberculosis. We suggest that core biopsy should be used in preference to lymph node excision, as it can be performed under local anaesthetic outside the operating theatre. A proposed algorithm for diagnostic management is included.

The effectiveness and cost-effectiveness of biomarkers for the prioritisation of patients awaiting coronary revascularisation: a systematic review and decision model.

OBJECTIVE: To determine the effectiveness and cost-effectiveness of a range of strategies based on conventional clinical information and novel circulating biomarkers for prioritising patients with stable angina awaiting coronary artery bypass grafting (CABG). DATA SOURCES: MEDLINE and EMBASE were searched from 1966 until 30 November 2008. REVIEW METHODS: We carried out systematic reviews and meta-analyses of literature-based estimates of the prognostic effects of circulating biomarkers in stable coronary disease. We assessed five routinely measured biomarkers and the eight emerging (i.e. not currently routinely measured) biomarkers recommended by the European Society of Cardiology Angina guidelines. The cost-effectiveness of prioritising patients on the waiting list for CABG using circulating biomarkers was compared against a range of alternative formal approaches to prioritisation as well as no formal prioritisation. A decision-analytic model was developed to synthesise data on a range of effectiveness, resource use and value parameters necessary to determine cost-effectiveness. A total of seven strategies was evaluated in the final model. RESULTS: We included 390 reports of biomarker effects in our review. The quality of individual study reports was variable, with evidence of small study (publication) bias and incomplete adjustment for simple clinical information such as age, sex, smoking, diabetes and obesity. The risk of cardiovascular events while on the waiting list for CABG was 3 per 10,000 patients per day within the first 90 days (184 events in 9935 patients with a mean of 59 days at risk). Risk factors associated with an increased risk, and included in the basic risk equation, were age, diabetes, heart failure, previous myocardial infarction and involvement of the left main coronary artery or three-vessel disease. The optimal strategy in terms of cost-effectiveness considerations was a prioritisation strategy employing biomarker information. Evaluating shorter maximum waiting times did not alter the conclusion that a prioritisation strategy with a risk score using estimated glomerular filtration rate (eGFR) was cost-effective. These results were robust to most alternative scenarios investigating other sources of uncertainty. However, the cost-effectiveness of the strategy using a risk score with both eGFR and C-reactive protein (CRP) was potentially sensitive to the cost of the CRP test itself (assumed to be 6 pounds in the base-case scenario). CONCLUSIONS: Formally employing more information in the prioritisation of patients awaiting CABG appears to be a cost-effective approach and may result in improved health outcomes. The most robust results relate to a strategy employing a risk score using conventional clinical information together with a single biomarker (eGFR). The additional prognostic information conferred by collecting the more costly novel circulating biomarker CRP, singly or in combination with other biomarkers, in terms of waiting list prioritisation is unlikely to be cost-effective.

The effect of mGlu8 deficiency in animal models of psychiatric diseases.

The metabotropic glutamate receptor subtype 8 (mGlu(8)) is presynaptically located and regulates the release of the transmitter. Dysfunctions of this mechanism are involved in the pathophysiology of different psychiatric disorders. mGlu(8) deficient mice have been previously investigated in a range of studies, but the results are contradictory and there are still many open questions. Therefore, we tested mGlu(8)-deficient animals in different behavioral tasks that are commonly used in neuropsychiatric research. Our results show a robust contextual fear deficit in mGlu(8)-deficient mice. Furthermore, novel object recognition, chlordiazepoxide-facilitated extinction of operant conditioning and the acoustic startle response were attenuated by mGlu(8) deficiency. We found no changes in sensory processing, locomotor activity, prepulse inhibition, phencyclidine-induced changes in locomotion or prepulse inhibition, operant conditioning, conditioned fear to a discrete cue or in animal models of innate fear and post-traumatic stress disorder. We conclude that mGlu(8) might be a potential target for disorders with pathophysiological changes in brain areas where mGlu(8) modulates glutamate and gamma-amino butyric acid (GABA) transmission. Our data especially point to anxiety disorders involving exaggerated contextual fear, such as generalized anxiety disorders, and to conditions with disturbed declarative memory.

Efficient copackaging and cotransport yields postsynaptic colocalization of neuromodulators associated with synaptic plasticity.

Recent data suggest that tissue plasminogen activator (tPA) influences long-term plasticity at hippocampal synapses by converting plasminogen into plasmin, which then generates mature brain-derived neurotrophic factor (mBDNF) from its precursor, proBDNF. Motivated by this hypothesis, we used fluorescent chimeras, expressed in hippocampal neurons, to elucidate (1) mechanisms underlying plasminogen secretion from hippocampal neurons, (2) if tPA, plasminogen, and proBDNF are copackaged and cotransported in hippocampal neurons, especially within dendritic spines, and (3) mechanisms mediating the transport of these neuromodulators to sites of release. We find that plasminogen chimeras traffic through the regulated secretory pathway of hippocampal neurons in dense-core granules (DCGs) and that tPA, plasminogen, and proBDNF chimeras are extensively copackaged in DCGs throughout hippocampal neurons. We also find that 80% of spines that contain DCGs contain chimeras of these neuromodulators in the same DCG. Finally, we demonstrate, for the first time, that neuromodulators undergo cotransport along dendrites in rapidly mobile DCGs, indicating that neuromodulators can be efficiently recruited into active spines. These results support the hypothesis that tPA mediates synaptic activation of BDNF by demonstrating that tPA, plasminogen, and proBDNF colocalize in DCGs in spines, where these neuromodulators can undergo activity-dependent release and then interact and/or mediate changes that influence synaptic efficacy. The results also raise the possibility that frequency-dependent changes in extents of neuromodulator release from DCGs influence the direction of plasticity at hippocampal synapses by altering the relative proportions of two proteins, mBDNF and proBDNF, that exert opposing effects on synaptic efficacy.

Neck lumps and head and neck tumours in children.

This article discusses the presentation, investigation and treatment of both benign and malignant lumps encountered in the head and neck region in children.

mGluR7 facilitates extinction of aversive memories and controls amygdala plasticity.

Formation and extinction of aversive memories in the mammalian brain are insufficiently understood at the cellular and molecular levels. Using the novel metabotropic glutamate receptor 7 (mGluR7) agonist AMN082, we demonstrate that mGluR7 activation facilitates the extinction of aversive memories in two different amygdala-dependent tasks. Conversely, mGluR7 knockdown using short interfering RNA attenuated the extinction of learned aversion. mGluR7 activation also blocked the acquisition of Pavlovian fear learning and its electrophysiological correlate long-term potentiation in the amygdala. The finding that mGluR7 critically regulates extinction, in addition to acquisition of aversive memories, demonstrates that this receptor may be relevant for the manifestation and treatment of anxiety disorders.

Estrogen receptor alpha and beta profiling in human breast cancer.

BACKGROUND: The identification of a second estrogen receptor (ER-beta) has significant implications for therapeutic strategy in breast cancer management arising from the potential agonist effect of Tamoxifen at estrogen receptor sites and as such, antiestrogen therapy may be inappropriate in patients with a dominance of ER-beta. METHODS: To determine the proportion of breast cancer patients who may be so at risk, we developed a novel multiplexed RT-PCR technique to establish the relative ER-alpha and ER-beta levels in 53 primary breast cancers, 11 normal breast tissues and six cell lines. We further assessed the prognostic significance of receptor status relative to the Nottingham prognostic index (NPI). The ER-alpha and ER-beta status was also determined by immunohistochemistry using previously published and 'in-house' scoring systems. RESULTS: Using RT-PCR analysis, 46 tumours were hormone receptor positive (ER+) with 42 displaying ER-alpha predominance. Comparison with immunohistochemistry demonstrated 44/53 (ER-alpha) and 27/50 (ER-beta) concordance rates. There was no significant difference in the NPI between ER-alpha and ER-beta predominant cohorts or between ER+ and ER- cohorts. CONCLUSION: This study identifies the existence of a subgroup of ER+ patients in whom Tamoxifen therapy may be inappropriate and has significant implications for adjuvant therapy of primary breast cancer.

Public and private collaboration in establishing a young person's sexual health clinic in a commercial setting.

OBJECTIVE: To define the key factors and constraints in public-private sector collaboration in establishing and delivering a young person's sexual health clinic within an existing commercial establishment. CONSULTATION, PLANNING AND IMPLEMENTATION PHASES: Consultations were held between the Health Promotion Department, family planning and commercial outlets, resulting in the establishment of the UK's first sexual health service within commercial premises. Once the clinic had been operational for 6 months, a single researcher carried out semi-structured interviews with 13 staff representing all levels within the partner organisations. POST-IMPLEMENTATION INTERVIEWS: There was agreement by all interviewees on the objectives of the clinic. The problems encountered during the establishment of the service were with the legislation pertaining to pharmacies and the adverse press coverage of a minority public view of the provision of sexual health services to young people. No respondent identified conflict between the aims of the clinic and the strategic objectives of their organisation. RECOMMENDATIONS: Common aims are imperative for successful interagency working. Wider initial consultations may have helped to identify potential problems and confirm common aims at an earlier stage of the development of the project. The involvement of senior management may also have improved the smooth running of the project.

Evaluation of a young person's sexual health service in a commercial setting.

OBJECTIVE: To determine the acceptability and accessibility of a sexual health service for young people in a city centre pharmacy. DESIGN: Prospective qualitative survey of clients attending a new sexual health service, including client characteristics and semi-structured interviews. PARTICIPANTS: Clients attending the service between January and May 1999. MAIN OUTCOME MEASURES: Social demographics, reasons for attendance and consultation outcomes for clients together with their views of the service. RESULTS: A total of 98 clients (average of three clients per session) attended from January to May 1999, ranging from 14 to 39 years of age. Clients came from 41 postcode areas of the city (which has over 80 postcode areas) and neighbouring districts, covering all social strata. Only four clients had never been sexually active; 53 clients attended for emergency contraception, with 26 attending for hormonal contraception. A total of 93% of those asked were either satisfied or very satisfied with the opening times. All clients were satisfied or very satisfied with the clinic location. CONCLUSIONS: The setting of a sexual health service for young people in a city centre pharmacy allows access from a wide area. The timing and location of the service were the most commonly quoted reasons for attendance. All clients were asked to participate in a semi-structured interview, unless the interviewer was already engaged; results were obtained for 66 clients (67% of attendees).

Bradykinin does not mediate cutaneous active vasodilation during heat stress in humans.

To test the hypothesis that bradykinin effects cutaneous active vasodilation during hyperthermia, we examined whether the increase in skin blood flow (SkBF) during heat stress was affected by blockade of bradykinin B(2) receptors with the receptor antagonist HOE-140. Two adjacent sites on the forearm were instrumented with intradermal microdialysis probes for local delivery of drugs in eight healthy subjects. HOE-140 was dissolved in Ringer solution (40 microM) and perfused at one site, whereas the second site was perfused with Ringer alone. SkBF was monitored by laser-Doppler flowmetry (LDF) at both sites. Mean arterial pressure (MAP) was monitored from a finger, and cutaneous vascular conductance (CVC) was calculated (CVC = LDF/MAP). Water-perfused suits were used to control body temperature and evoke hyperthermia. After hyperthermia, both microdialysis sites were perfused with 28 mM nitroprusside to effect maximal vasodilation. During hyperthermia, CVC increased at HOE-140 (69 +/- 2% maximal CVC, P < 0.01) and untreated sites (65 +/- 2% maximal CVC, P < 0.01). These responses did not differ between sites (P > 0.05). Because the bradykinin B(2)-receptor antagonist HOE-140 did not alter SkBF responses to heat stress, we conclude that bradykinin does not mediate cutaneous active vasodilation.

Uterine balloon therapy for menorrhagia: a feasibility study of its use in the community setting.

OBJECTIVES: To determine whether uterine balloon therapy (UBT) for menorrhagia can be performed safely in the community setting, obviating the need for hospital admission or general anaesthesia. DESIGN: Prospective case studies of 20 women undergoing Thermachoice endometrial ablation for menorrhagia. SETTING: Glasgow Centre for Family Planning and Reproductive Health Care, Greater Glasgow Primary Care NHS Trust, Glasgow, UK. PARTICIPANTS: Twenty women with menorrhagia unresponsive to medical therapy. MAIN OUTCOME MEASURES: Pain levels experienced by women during the procedure, measured by visual analogue scores and analgesia requirements postoperatively. RESULTS: Pain scores were in the range 0.1-6.6 (median 1.1) for outpatient hysteroscopy, compared to 0.1-9.8 (median 4.0) for uterine balloon therapy. No procedure was abandoned due to pain. CONCLUSION: UBT performed under local anaesthetic is tolerated well by patients. It is an effective treatment for menorrhagia, which is safe and easy to perform in the community setting.

The alpha 2 adrenoceptor antagonists RX 821002 and yohimbine delay-dependently impair choice accuracy in a delayed non-matching-to-position task in rats.

RATIONALE: alpha 2 adrenoceptor mechanisms appear to play a role in the performance of delayed response working memory tasks but there are contradictory results. OBJECTIVE: To investigate whether RX 821002 (2-methoxy-idazoxan) and yohimbine and would affect the performance of the delayed non-matching-to-position (DNMTP) task in rats and compare the effects to those of the cholinergic antagonist scopolamine. METHODS: Male Lister Hooded rats trained to criterion in an operant DNMTP task (0-48 s delay intervals) were administered vehicle, RX 821002 (0.3, 1, 3 mg/kg s.c.), yohimbine (1, 3 mg/kg. s.c.) or scopolamine (0.05 mg/kg, s.c.). Together with choice accuracy, the motor performance of the task was measured. RESULTS: It was found that: (1) both RX 821002 and yohimbine statistically significantly reduced choice accuracy dose- and delay-dependently and in a similar magnitude to that of scopolamine while modifying the motor aspects of task performance delay-independently and (2) RX 821002 produced mainly rate-decreasing effects. Yohimbine exerted stimulatory effects at the lowest dose and rate-decreasing effects at the highest dose, a profile consistent with that already described in operant tasks. CONCLUSION: The results confirm that alpha 2 antagonists delay-dependently impair choice accuracy in a delayed-response paradigm.

MRI analysis of the changes in apparent water diffusion coefficient, T(2) relaxation time, and cerebral blood flow and volume in the temporal evolution of cerebral infarction following permanent middle cerebral artery occlusion in rats.

Detailed knowledge of similarities and differences between animal models and human stroke is decisive for selecting clinically effective drugs based on efficacy data obtained preclinically. Differences in the temporal evolution of stroke pathologies between animal models and man have been reported. In view of the importance of this issue for the development of neuroprotective treatments, the temporal evolution of stroke pathologies in the rat permanent middle cerebral artery occlusion (pMCAO) model has been evaluated with magnetic resonance imaging modalities under experimental conditions matching as close as possible those used in humans. Changes in the ipsilateral and contralateral cortex and striatum of cerebral blood flow (CBF) and volume (CBV), apparent diffusion coefficient (ADC), and spin-spin relaxation time (T(2)), as well as total cortical and striatal infarct volumes, calculated from CBF, ADC, and T(2) maps, were determined starting 1 h up to 216 h post-pMCAO. The temporal evolution of the MRI parameters in this rat model was similar to that observed in humans. In particular, the ADC values were decreased for more than 3 days and returned back to baseline between 4 to 8 days, to increase by day 9 only. Thus the stroke pathology in this rat model develops at a similar pace as in stroke patients arguing against a fundamental difference in the mechanisms involved. The infarct volumes however develop differently in this rat model as they invariably increase over the first 48 h, while in humans the evolution of infarct volume is slower and more heterogeneous.

Mammary tumor induction and premature ovarian failure in ApcMin mice are not enhanced by Brca2 deficiency.

Inherited BRCA2 mutations predispose individuals to breast cancer and increase risk at other sites. Recent studies have suggested a role for the APC I1307K allele as a low-penetrance breast cancer susceptibility gene that enhances the phenotypic effects of BRCA1 and BRCA2 mutations. To model the consequences of inheriting mutant alleles of the BRCA2 and APC tumor suppressor genes, we examined tumor outcome in C57BL/6 mice with mutations in the Brca2 and Apc genes. We hypothesized that if the Brca2 and Apc genes were interacting to influence mammary tumor susceptibility, then mammary tumor incidence and/or multiplicity would be altered in mice that had inherited mutations in both genes. Female and male offspring treated with a single IP injection of 50 mg/kg N-ethyl-N-nitrosourea (ENU) at 35 days of age developed mammary adenoacanthomas by 100 days of age. The female Apc-mutant and Brca2/Apc double-mutant progeny had mean mammary tumor multiplicities of 6.7+/-2.8 and 7.2+/-2.7, respectively, compared to wild-type and Brca2-mutant females, which had mean mammary tumor multiplicities of 0.1+/-0.4 and 0.3+/-0.5, respectively. Female ENU-treated Apc-mutant and Brca2/Apc double heterozygotes were also susceptible to premature ovarian failure. Thus, the inheritance of an Apc mutation predisposes ENU-treated female and male mice to mammary tumors and, in the case of female mice, to ovarian failure. These results indicate that mammary tumor development in Apc-mutant mice can progress independently of ovarian hormones. The Apc mutation-driven phenotypes were not modified by mutation of Brca2, perhaps because Brca2 acts in a hormonally dependent pathway of mammary carcinogenesis.