PREDICT-GTN 2: Two-factor streamlined models match FIGO performance in gestational trophoblastic neoplasia

OBJECTIVE

The International Federation of Gynecology and Obstetrics (FIGO) scoring system uses the sum of eight risk-factors to predict single-agent chemotherapy resistance in Gestational Trophoblastic Neoplasia (GTN). To improve ease of use, this study aimed to generate: (i) streamlined models that match FIGO performance and; (ii) visual-decision aids (nomograms) for guiding management.

METHODS

Using training (n = 4191) and validation datasets (n = 144) of GTN patients from two UK specialist centres, logistic regression analysis generated two-factor models for cross-validation and exploration. Performance was assessed using true and false positive rate, positive and negative predictive values, Bland-Altman calibration plots, receiver operating characteristic (ROC) curves, decision-curve analysis (DCA) and contingency tables. Nomograms were developed from estimated model parameters and performance cross-checked upon the training and validation dataset.

RESULTS

Three streamlined, two-factor models were selected for analysis: (i) M1, pre-treatment hCG + history of failed chemotherapy; (ii) M2, pre-treatment hCG + site of metastases and; (iii) M3, pre-treatment hCG + number of metastases. Using both training and validation datasets, these models showed no evidence of significant discordance from FIGO (McNemar's test p > 0.78) or across a range of performance parameters. This behaviour was maintained when applying algorithms simulating the logic of the nomograms.

CONCLUSIONS

Our streamlined models could be used to assess GTN patients and replace FIGO, statistically matching performance. Given the importance of imaging parameters in guiding treatment, M2 and M3 are favoured for ongoing validation. In resource-poor countries, where access to specialist centres is problematic, M1 could be pragmatically implemented. Further prospective validation on a larger cohort is recommended.

PREDICT-GTN 1: Can we improve the FIGO scoring system in gestational trophoblastic neoplasia?

Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.

Computed tomography chest imaging offers no advantage over chest X-ray in the initial assessment of gestational trophoblastic neoplasia

BACKGROUND

The International Federation of Gynaecology and Obstetrics (FIGO) score identifies gestational trophoblastic neoplasia (GTN) patients as low- or high-risk of single-agent chemotherapy resistance (SACR). Computed tomography (CT) has greater sensitivity than chest X-ray (CXR) in detecting pulmonary metastases, but effects upon outcomes remain unclear.

METHODS

Five hundred and eighty-nine patients underwent both CXR and CT during GTN assessment. Treatment decisions were CXR based. The number of metastases, risk scores, and risk category using CXR versus CT were compared. CT-derived chest assessment was evaluated as impact upon treatment decision compared to patient outcome, incidence of SACR, time-to-normal human chorionic gonadotrophin hormone (TNhCG), and primary chemotherapy resistance (PCR).

RESULTS

Metastasis detection (p < 0.0001) and FIGO score (p = 0.001) were higher using CT versus CXR. CT would have increased FIGO score in 188 (31.9%), with 43 re-classified from low- to high-risk, of whom 23 (53.5%) received curative single-agent chemotherapy. SACR was higher when score (p = 0.044) or risk group (p < 0.0001) changed. Metastases on CXR (p = 0.019) but not CT (p = 0.088) lengthened TNhCG. Logistic regression analysis found no difference between CXR (area under the curve (AUC) = 0.63) versus CT (AUC = 0.64) in predicting PCR.

CONCLUSIONS

CT chest would improve the prediction of SACR, but does not influence overall treatment outcome, TNhCG, or prediction of PCR. Lower radiation doses and cost mean ongoing CXR-based assessment is recommended.

Salivary Cortisone to Estimate Cortisol Exposure and Sampling Frequency Required Based on Serum Cortisol Measurements

CONTEXT

Population studies frequently measure cortisol as a marker of stress, and excess cortisol is associated with increased mortality. Cortisol has a circadian rhythm, and frequent blood sampling is impractical to assess cortisol exposure. We investigated measuring salivary cortisone and examined the sampling frequency required to determine cortisol exposure.

METHODS

Serum and saliva with cortisol and cortisone were measured by liquid chromatography-tandem mass spectrometry in independent cohorts. The relationship between serum cortisol and salivary cortisone was analyzed in cohort 1 using a linear mixed effects model. The resulting fixed effects component was applied to cohort 2. Saliva cannot easily be collected when a patient is sleeping, so we determined the minimum sampling required to estimate cortisol exposure [estimated area under the curve (eAUC)] using 24-hour cortisol profiles (AUC24) and calculated the relative error (RE) for eAUC.

RESULTS

More than 90% of variability in salivary cortisone could be accounted for by change in serum cortisol. A single serum cortisol measurement was a poor estimate of AUC24, especially in the morning or last thing at night (RE >68%); however, three equally spaced samples gave a median RE of 0% (interquartile range, -15.6% to 15.1%). In patients with adrenal incidentalomas, eAUC based on three serum cortisol samples showed a difference between those with autonomous cortisol secretion and those without (P = 0.03).

INTERPRETATION

Accepting that most people sleep 7 to 8 hours, ∼8-hourly salivary cortisone measurements provide a noninvasive method of estimating 24-hour cortisol exposure for population studies.

Use of salivary cortisol and cortisone in the high- and low-dose synacthen test

CONTEXT

Salivary cortisone reflects serum cortisol levels, is more sensitive than salivary cortisol at lower values of serum cortisol and is noninvasive.

OBJECTIVE

To investigate the relationship between serum cortisol and salivary cortisol and cortisone following low- and high-dose synacthen.

DESIGN AND SETTING

Prospective pharmacodynamic studies in clinical research facilities.

PARTICIPANTS AND INTERVENTION

Thirty-five dexamethasone-suppressed, healthy adult males underwent an intravenous synacthen test: N = 23 low-dose (1 mcg), N = 12 high-dose (250 mcg). Paired serum and salivary samples were taken at 15 sampling points over 120 minutes.

MAIN OUTCOME MEASURE

Serum cortisol and salivary cortisol and cortisone were analysed for correlations and by a mixed-effects model.

RESULTS

At baseline, the correlation between serum cortisol and salivary cortisol was weak with many samples undetectable (r = .45, NS), but there was a strong correlation with salivary cortisone (r = .94, P < .001). Up to 50 minutes following synacthen, the correlation coefficient between serum cortisol and salivary cortisol and cortisone was <0.8, but both had a stronger correlation at 60 minutes (salivary cortisol r = .89, P < .001, salivary cortisone r = .85, P < .001). The relationship was examined excluding samples in the dynamic phase (baseline to 60 minutes). Salivary cortisol and cortisone showed a close relationship to serum cortisol. Salivary cortisone showed the stronger correlation: salivary cortisol r = .82, P < .001, salivary cortisone r = .96, P < .001.

CONCLUSION

Following synacthen, both salivary cortisol and cortisone reflect serum cortisol levels, but there is a lag in their rise up to 60 minutes. The results support further research for possible future use of a 60-minute salivary cortisone measurement during the synacthen test.

Resetting the Abnormal Circadian Cortisol Rhythm in Adrenal Incidentaloma Patients With Mild Autonomous Cortisol Secretion

CONTEXT

Adrenal incidentalomas (AIs) are found commonly on axial imaging. Around 30% exhibit autonomous cortisol secretion (ACS) associated with increased cardiovascular events and death.

OBJECTIVE

We hypothesized that AI/ACS patients have an abnormal cortisol rhythm that could be reversed by use of carefully timed short-acting cortisol synthesis blockade, with improvement in cardiovascular disease markers.

DESIGN, SETTING, AND PARTICIPANTS

In a phase 1/2a, prospective study (Eudract no. 2012-002586-35), we recruited six patients with AI/ACS and two control groups of six sex-, age-, and body mass index-matched individuals: (1) patients with AI and no ACS (AI/NoACS) and (2) healthy volunteers with no AI [healthy controls (HC)]. Twenty-four-hour circadian cortisol analysis was performed to determine any differences between groups and timing of intervention for cortisol lowering using the 11β-hydroxylase inhibitor metyrapone. Circadian profiles of serum interleukin-6 (IL-6) were assessed.

RESULTS

Serum cortisol levels in group AI/ACS were significantly higher than both group AI/NoACS and group HC from 6 pm to 10 pm [area under the curve (AUC) difference: 0.81 nmol/L/h; P = 0.01] and from 10 pm to 2 am (AUC difference: 0.86 nmol/L/h; P < 0.001). In light of these findings, patients with ACS received metyrapone 500 mg at 6 pm and 250 mg at 10 pm, and cortisol rhythms were reassessed. Postintervention evening serum cortisol was lowered, similar to controls [6 pm to 10 pm (AUC difference: -0.06 nmol/L/h; P = 0.85); 10 pm to 2 am (AUC difference: 0.10 nmol/L/h; P = 0.76)]. Salivary cortisone showed analogous changes. IL-6 levels were elevated before treatment [10 pm to 2 pm (AUC difference: 0.42 pg/mL/h; P = 0.01)] and normalized post treatment.

CONCLUSIONS

In AI/ACS, the evening and nocturnal cortisol exposure is increased. Use of timed evening doses of metyrapone resets the cortisol rhythm to normal. This unique treatment paradigm is associated with a reduction in the cardiovascular risk marker IL-6.

Using the NANA toolkit at home to predict older adults' future depression

BACKGROUND

Depression is currently underdiagnosed among older adults. As part of the Novel Assessment of Nutrition and Aging (NANA) validation study, 40 older adults self-reported their mood using a touchscreen computer over three, one-week periods. Here, we demonstrate the potential of these data to predict future depression status.

METHODS

We analysed data from the NANA validation study using a machine learning approach. We applied the least absolute shrinkage and selection operator with a logistic model to averages of six measures of mood, with depression status according to the Geriatric Depression Scale 10 weeks later as the outcome variable. We tested multiple values of the selection parameter in order to produce a model with low deviance. We used a cross-validation framework to avoid overspecialisation, and receiver operating characteristic (ROC) curve analysis to determine the quality of the fitted model.

RESULTS

The model we report contained coefficients for two variables: sadness and tiredness, as well as a constant. The cross-validated area under the ROC curve for this model was 0.88 (CI: 0.69-0.97).

LIMITATIONS

While results are based on a small sample, the methodology for the selection of variables appears suitable for the problem at hand, suggesting promise for a wider study and ultimate deployment with older adults at increased risk of depression.

CONCLUSIONS

We have identified self-reported scales of sadness and tiredness as sensitive measures which have the potential to predict future depression status in older adults, partially addressing the problem of underdiagnosis.

Technology for Early Detection of Depression and Anxiety in Older People

Under-diagnosis of depression and anxiety is common in older adults. This project took a mixed methods approach to explore the application of machine learning and technology for early detection of these conditions. Mood measures collected with digital technologies were used to predict depression and anxiety status according to the Geriatric Depression Scale (GDS) and the Hospital Anxiety and Depression Scale (HADS). Interactive group activities and interviews were used to explore views of older adults and healthcare professionals on this approach respectively. The results show good potential for using a machine learning approach with mood data to predict later depression, though prospective results are preliminary. Qualitative findings highlight motivators and barriers to use of mental health technologies, as well as usability issues. If consideration is given to these issues, this approach could allow alerts to be provided to healthcare staff to draw attention to service users who may go on to experience depression.

Salivary Cortisone Reflects Cortisol Exposure Under Physiological Conditions and After Hydrocortisone

In this study we tested the use of salivary cortisol and cortisone as alternatives to serum cortisol. Salivary cortisol is often undetectable and contaminated by hydrocortisone. Salivary cortisone strongly reflects serum cortisol.

Hormonal circadian rhythms in patients with congenital adrenal hyperplasia: identifying optimal monitoring times and novel disease biomarkers

OBJECTIVES

The treatment goal in congenital adrenal hyperplasia (CAH) is to replace glucocorticoids while avoiding androgen excess and iatrogenic Cushing's syndrome. However, there is no consensus on how to monitor disease control. Our main objectives were to evaluate hormonal circadian rhythms and use these profiles to identify optimal monitoring times and novel disease biomarkers in CAH adults on intermediate- and long-acting glucocorticoids.

DESIGN

This was an observational, cross-sectional study at the National Institutes of Health Clinical Center in 16 patients with classic CAH.

METHODS

Twenty-four-hour serum sampling for ACTH, 17-hydroxyprogesterone (17OHP), androstenedione (A4), androsterone, DHEA, testosterone, progesterone and 24-h urinary pdiol and 5β-pdiol was carried out. Bayesian spectral analysis and cosinor analysis were performed to detect circadian rhythmicity. The number of hours to minimal (TminAC) and maximal (TmaxAC) adrenocortical hormone levels after dose administration was calculated.

RESULTS

A significant rhythm was confirmed for ACTH (r(2), 0.95; P<0.001), 17OHP (r(2), 0.70; P=0.003), androstenedione (r(2), 0.47; P=0.043), androsterone (r(2), 0.80; P<0.001), testosterone (r(2), 0.47; P=0.042) and progesterone (r(2), 0.64; P=0.006). The mean (s.d.) TminAC and TmaxAC for 17OHP and A4 were: morning prednisone (4.3 (2.3) and 9.7 (3.5) h), evening prednisone (4.5 (2.0) and 10.3 (2.4) h), and daily dexamethasone (9.2 (3.5) and 16.4 (7.2) h). AUC0-24 h progesterone, androsterone and 24-h urine pdiol were significantly related to 17OHP.

CONCLUSION

In CAH patients, adrenal androgens exhibit circadian rhythms influenced by glucocorticoid replacement. Measurement of adrenocortical hormones and interpretation of results should take into account the type of glucocorticoid and time of dose administration. Progesterone and backdoor metabolites may provide alternative disease biomarkers.

Assisted reproductive technology treatment outcomes

Information on the outcomes of ART treatments in Ireland is not readily available to Irish practitioners. The data for hospital affiliated clinics has been made available for many years and is included in the hospital reports. We present a 10-year analysis of the Irish ART results voluntarily reported by six out of seven IVF clinics. The data was collected from published ESHRE reports and from results (2007-8) not yet published. Data collected included: number of clinics and ART cycles, female age, clinical and multiple pregnancy rates and treatment complications. The clinical pregnancy rate per embryo transfer was 31.7% for IVF and 29.8% for ICSI. The proportion of singleton, twin and triplet deliveries for IVF and ICSI combined was 75%, 23.35% and 1.64%. The rate of ovarian hyperstimulation was 0.8%. ART practice in Ireland is safe, effective and responsible. Financial and societal savings could result from the introduction of state funded IVF with compulsory eSET where recommended.

The development of IVF practice in Ireland: a personal view

This paper traces the development of in vitro fertilization (IVF) in the Republic of Ireland from when the first attempts at using this technique were carried out in 1985 up to the present. Clinical changes are chronicled principally using the personal work of the author and his colleagues as representative of the day. The impact of the Catholic Church and the alterations in Medical Council governance guidelines over the years as these reflect societal changes are highlighted. The potential role of other regulators including Irish case law and the EU Tissue directive are discussed as well as the almost invariable private practice nature of the services provided and the various ways in which costs have been alleviated.

Psychosocial trends in couples prior to commencement of in vitro fertilisation (IVF) treatment

Facing infertility and undergoing fertility treatment can create emotional turmoil in couples' lives. It is essential for fertility therapy providers to assess the coping and communication strategies of couples before treatment in order to provide appropriate support. We performed a two time point (year 2003 & year 2009) cross-sectional study of patients attending our services to undergo in vitro fertilisation. All couples attending the Human Assisted Reproduction Ireland Unit, a tertiary referral academic centre at the Rotunda Hospital, were requested to complete a psychosocial questionnaire before commencing the treatment. The questions assessed couples' understanding of their own infertility, family background and support, relationship traits and stress levels prior to commencing fertility treatment. A total of 180 patients participated in the study. Our findings showed that within a 6-year time span, couples' attitudes have changed significantly. Compared to 6 years ago, couples now have a better understanding of infertility and are seeking treatment quicker. Interestingly, we showed higher stress levels nowadays with fewer couples following routine stress management. We also identified specific gender differences in that women have a more open attitude in discussing infertility and seeking more support from friends and family compared to men.

Much of the variation in breast pathology quality assurance data in the UK can be explained by the random order in which cases arrive at individual centres, but some true outliers do exist

AIMS

To investigate the role of random temporal order of patient arrival at screening centres in the variability seen in rates of node positivity and breast cancer grade between centres in the NHS Breast Screening Programme.

METHODS AND RESULTS

Computer simulations were performed of the variation in node positivity and breast cancer grade with the random temporal arrival of patients at screening centres based on national UK audit data. Cumulative mean graphs of these data were plotted. Confidence intervals for the parameters were generated, using the binomial distribution. UK audit data were plotted on these control limit graphs. The results showed that much of the variability in the audit data could be accounted for by the effects of random order of arrival of cases at the screening centres. Confidence intervals of 99.7% identified true outliers in the data.

CONCLUSIONS

Much of the variation in breast pathology quality assurance data in the UK can be explained by the random order in which cases arrive at individual centres. Control charts with confidence intervals of 99.7% plotted against the number of reported cases are useful tools for identification of true outliers.

Stathmin is expressed by the proliferating hepatocytes during liver regeneration

Aim-To determine the liver cell populations that express the phylogenetically conserved cytosolic protein stathmin during liver regeneration.Methods-Double immunostaining for stathmin and the Ki67 antigen was performed on sections of formaldehyde fixed, paraffin wax embedded tissues from 31 liver specimens. These included a variety of disease conditions characterised by some degree of hepatocyte regeneration. Quantitative western blot analysis was performed on 22 of these specimens.Results-Variable amounts of stathmin protein were detected by western blotting in all of the specimens examined. Stathmin was not detected in three cases of histologically normal liver. On immunostaining, stathmin was demonstrated in a proportion of hepatocytes as well as lymphoid inflammatory cells and other tissue elements. In all cases most of these stathmin positive cells showed nuclear positivity for the Ki67 antigen.Conclusions-Stathmin is expressed by proliferating hepatocytes but not by resting hepatocytes. Thus, it is likely that the protein has a function important to cell proliferation as opposed to cell differentiation.

Fertility after abdominal myomectomy

This study aimed to evaluate the morbidity and pregnancy outcome of myomectomy in infertile women with uterine fibroids. This was a cross-sectional study. Records were reviewed for 100 consecutive women in the Rotunda Hospital who underwent myomectomy in the years 1995-1996. A questionnaire regarding subsequent fertility was sent. The study was carried out in the infertility unit at the Rotunda Hospital, Dublin, Ireland. Seventy-five women responded. Multiple myomectomy was performed in 52 (70%). Mean fibroid size was 6.8 cm (range 2-14.5 cm). Nine women (12%) developed complications; five had menstrual problems, two had wound discomfort and two had abdominal discomfort. Twenty-five women (33%) became pregnant. Seven (28%) were IVF pregnancies. Overall six (24%) miscarried. In 19 of 25, pregnancy occurred where fibroids were the only identifiable cause of infertility. We conclude that abdominal myomectomy is associated with a favourable outcome in infertile women particularly if no other confounding variable is present.

Cadherin switching dictates the biology of transitional cell carcinoma of the bladder: ex vivo and in vitro studies

Bladder cancer is the fifth most common malignancy in the UK. Clinically, the most important process in determining prognosis is the development of invasion, initially of the lamina propria and then beyond as these transitional cell carcinomas (TCCs) progress from stage pT1 to stages T2+. Cadherins and catenins are the main mediators of cell-cell interactions in epithelial tissues, and loss of membranous E-cadherin immunoreactivity is strongly correlated with high grade, advanced stage and poor prognosis in bladder cancer and other malignancies. However, the role of P-cadherin is yet to be fully elucidated in bladder TCC. The objectives of this study were to establish how the expression of cadherins and catenins determines clinical and in vitro behaviour in bladder TCC. Utilizing immunohistochemistry, immunofluorescence and western blotting, we demonstrated a significant reduction in the expression of E-cadherin and beta-catenin as grade and stage of bladder TCC progress, accompanied by a significant increase in P-cadherin expression (all p < 0.05, Pearson's chi2 test). Increased P-cadherin expression was also associated with a significantly worse bladder cancer-specific survival (log rank p = 0.008), with Cox regression showing P-cadherin to be an independent prognostic factor. Utilizing a variety of tissue culture models in a range of functional studies, we demonstrated that P-cadherin mediates defective cell-cell adhesion and enhances anchorage-independent growth. The results provide evidence that increased P-cadherin expression promotes a more malignant and invasive phenotype of bladder cancer, and appears to have a novel role late in the disease.

Free triiodothyronine has a distinct circadian rhythm that is delayed but parallels thyrotropin levels

CONTEXT

TSH is known to have a circadian rhythm, but the relationship between this and any rhythm in T(4) and T(3) has not been clearly demonstrated.

OBJECTIVE

With a view to optimizing thyroid hormone replacement therapy, we have used modern assays for free T(4) (FT4) and free T(3) (FT3) to investigate circadian rhythmicity.

SETTING

The study was performed at a university hospital.

DESIGN AND SUBJECTS

This was a cross-sectional study in 33 healthy individuals with 24-h blood sampling (TSH in 33 and FT4 and FT3 in 29 individuals) and cosinor analysis.

RESULTS

Of the individuals, 100% showed a sinusoidal signal in TSH, for FT4 76%, and for FT3 86% (P < 0.05). For FT4 and FT3, the amplitude was low. For TSH the acrophase occurred at a clock time of 0240 h, and for FT3 approximately 90 minutes later at 0404 h. The group cosinor model predicts that TSH hormone levels remain above the mesor between 2020 and 0820 h, and for FT3 from 2200-1000 h. Cross correlation of FT3 with TSH showed that the peak correlation occurred with a delay of 0.5-2.5 h. When time-adjusted profiles of TSH and FT3 were compared, there was a strong correlation between FT3 and TSH levels (rho = 0.80; P < 0.0001). In contrast, cross correlation revealed no temporal relationship between FT4 and TSH.

CONCLUSIONS

FT3 shows a circadian rhythm with a periodicity that lags behind TSH, suggesting that the periodic rhythm of FT3 is due to the proportion of T(3) derived from the thyroid. Optimizing thyroid hormone replacement may need to take these rhythms into account.

Frozen-thawed transfer cycles: are they comparable with fresh?

Cryopreservation of zygotes and subsequent thaw and transfer is an established ART treatment. We assessed if success rates frozen-thawed (day 2) zygotes are comparable with the outcome in fresh cycles of treatment. We performed a prospective follow-up and analysis of all frozen (FZT) and fresh cycles of treatment during a 12 months period. One hundred and nineteen patients in the frozen-thawed and 652 in the fresh group had a transfer. The overall thaw-survival rate was 71.7%. Clinical pregnancy rates per thaw and transfer were respectively 15.1% and 21% in the frozen and 29.1% (per transfer) in the fresh group. Implantation rates in fresh and frozen cycles were 16% and 12.3% respectively. The pregnancy loss rate was higher in the FZT group (29% vs. 18.3%). Cryopreservation of good quality zygotes, after fresh transfer offers optimal success rates in subsequent frozen treatment. It also encourages consideration of elective single zygote transfers.

Impact of a New Formulation of Low-Dose Micronised Medroxyprogesterone and 17-beta Estradiol on Lipid Profiles in Menopausal Women

OBJECTIVE

To evaluate the impact of cyclical low-dose micronised medroxyprogesterone (5 mg/day for the last 12 days of each 28-day cycle) in combination with 17-beta estradiol (2 mg/day continuously) on lipid profiles in postmenopausal women treated for 12 months.

DESIGN AND SETTING

Open, noncomparative, prospective study carried out in general practice.

PATIENTS AND RESULTS

98 female patients were enrolled; seven failed to meet entry criteria, 20 withdrew after developing adverse events, three were lost to follow up and one withdrew for personal reasons; 67 (67.3%) completed 12 months' treatment. Levels of total cholesterol (6.42 mmol/L at baseline) fell 8.4% (p = 0.0001) after 12 months' treatment, while total triglycerides (1.39 mmol/L at baseline) increased by 12.2% (p = 0.007), low density lipoprotein cholesterol (4.27 mmol/L at baseline) fell 18.3% (p = 0.0001) and high density lipoprotein (HDL) cholesterol (1.59 mmol/L at baseline) increased by 6.9% (p = 0.0001). The most frequently reported adverse events were menorrhagia, breast tenderness, cervical polyps or cysts, bloating, fatigue or lethargy, influenza or influenza-like syndrome, back pain and headaches.

CONCLUSIONS

Treatment with oral micronised 17-beta estradiol 2 mg/day continuously and medroxyprogesterone 5 mg/day for 12 days of each 28-day cycle lead to changes in lipid profiles in postmenopausal women that had favourable implications for the risk of development of coronary heart disease. The 17-beta estradiol-induced increase in the level of HDL cholesterol was maintained during combination with low-dose cyclical medroxyprogesterone for 12 months.

Cholecystobronchial fistula secondary to adenomyomatosis of the gallbladder

A case of cholecystobronchial fistula secondary to adenomyomatosis of the gallbladder is described. A cholecystobronchial fistula is a very unusual cause of fistulation between the bronchial and biliary tree. This is only the fifth reported case in the English language literature.

Automatic covariate selection in logistic models for chest pain diagnosis: a new approach

A newly established method for optimizing logistic models via a minorization-majorization procedure is applied to the problem of diagnosing acute coronary syndromes (ACS). The method provides a principled approach to the selection of covariates which would otherwise require the use of a suboptimal method owing to the size of the covariate set. A strategy for building models is proposed and two models optimized for performance and for simplicity are derived via 10-fold cross-validation. These models confirm that a relatively small set of covariates including clinical and electrocardiographic features can be used successfully in this task. The performance of the models is comparable with previously published models using less principled selection methods. The models prove to be portable when tested on data gathered from three other sites. Whilst diagnostic accuracy and calibration diminishes slightly for these new settings, it remains satisfactory overall. The prospect of building predictive models that are as simple as possible for a required level of performance is valuable if data-driven decision aids are to gain wide acceptance in the clinical situation owing to the need to minimize the time taken to gather and enter data at the bedside.

From egg to offspring. Survival rates in in-vitro fertilisation: where does it go wrong?

This retrospective study examines the attrition that occurs from all eggs inseminated and fertilised through to babies taken home in an IVF fresh/frozen programme undertaken between 2001-4. Poor survival rates are to be found, particularly during the recognised in-vitro developmental stages, Present practice which promotes quantity from the start, increases problem potential, is wasteful and against the concept of one embryo one baby. This suggests the need to develop better criteria for egg selection for insemination thus enabling a rethink to the approach to ovarian stimulation of one of quality rather than quantity.

Maternal folate status and neural tube defects in Ireland: the need for a national food fortification program

To determine the present risk of a Neural Tube Defect [NTD] pregnancy in the caucasian primigravid population in Dublin by comparing the serum folate and red cell folate status of primigravid patients attending the first prenatal booking clinic with data from the late 80's. This Cross-sectional population study looking at blood folate status of over 400 sequential primigravid caucasian women with a singleton pregnancy, booking at less than or equal to 20 weeks gestation. All patients were attending a prenatal booking clinic at the Rotunda Hospital in Dublin during 2003-2004. Comparing serum and red cell folate values in 454 primigravid patients in 2003-4 to values to in a large case-control study based on over 56,000 women attending maternity hospitals in Dublin from 1986 to 1990. Just 13.9% of our patients took periconceptual folate, 33.5% of patients took folate in the first 20 weeks of pregnancy and 58.8% of mothers were taking no folate supplement. Overall, 30% of mothers had RCF levels below 400 ug/L--a level recommended as the minimum value required for protection. NTD risk occurred most frequently amongst patients with RCF levels between 300 and 400 ng/mL.

Evaluation of machine-learning methods for ligand-based virtual screening

Machine-learning methods can be used for virtual screening by analysing the structural characteristics of molecules of known (in)activity, and we here discuss the use of kernel discrimination and naive Bayesian classifier (NBC) methods for this purpose. We report a kernel method that allows the processing of molecules represented by binary, integer and real-valued descriptors, and show that it is little different in screening performance from a previously described kernel that had been developed specifically for the analysis of binary fingerprint representations of molecular structure. We then evaluate the performance of an NBC when the training-set contains only a very few active molecules. In such cases, a simpler approach based on group fusion would appear to provide superior screening performance, especially when structurally heterogeneous datasets are to be processed.

The hidden costs of IVF

Whether the payment is personal or funded via a third party, IVF is expensive. Clinical and drug costs are known and if necessary can be budgeted for. But, indirect expenses involved in participation also need to be considered. In order to find out what these latter might be, women attending Human Assisted Reproduction Ireland at the Rotunda Hospital Dublin completed prospectively a detailed questionnaire on all likely areas of extra expense during a single IVF cycle from down-regulation to zygote transfer. Four groups participated, divided according to their distance from the clinic. Group A were within Dublin and Group B within a 50 mile radius. Group C were between a 50-130 mile radius and Group D a 130-200 mile radius. Mean levels of costs increased with distance:- Group A 104 euros. to Group D 703 euros. Food, meals and accommodation were the main contributors. Travel time and time-off work also increased with distance. These were respectively, Group A to Group D 15hrs to 139hrs: 35hrs to 75hrs. The study demonstrates that significant extra expense in time and money can be spent in an IVF cycle over and above medical and drug costs. This must be advised prior to commencement. All other issues being equal, geographical location should be part of the decision as to which clinic to attend.

Virtual Screening Using Binary Kernel Discrimination: Analysis of Pesticide Data

This paper discusses the use of binary kernel discrimination (BKD) for identifying potential active compounds in lead-discovery programs. BKD was compared with established virtual screening methods in a series of experiments using pesticide data from the Syngenta corporate database. It was found to be superior to methods based on similarity searching and substructural analysis but inferior to a support vector machine. Similar conclusions resulted from application of the methods to a pesticide data set for which categorical activity data were available.

Virtual Screening Using Binary Kernel Discrimination: Effect of Noisy Training Data and the Optimization of Performance

Binary kernel discrimination (BKD) uses a training set of compounds, for which structural and qualitative activity data are available, to produce a model that can then be applied to the structures of other compounds in order to predict their likely activity. Experiments with the MDL Drug Data Report database show that the optimal value of the smoothing parameter, and hence the predictive power of BKD, is crucially dependent on the number of false positives in the training set. It is also shown that the best results for BKD are achieved using one particular optimization method for the determination of the smoothing parameter that lies at the heart of the method and using the Jaccard/Tanimoto coefficient in the kernel function that is used to compute the similarity between a test set molecule and the members of the training set.

Expression of receptor activator of nuclear factor kappabeta ligand (RANKL) and tumour necrosis factor related, apoptosis inducing ligand (TRAIL) in breast cancer, and their relations with osteoprotegerin, oestrogen receptor, and clinicopathological variables

BACKGROUND

Receptor activator of nuclear factor kappabeta ligand (RANKL) has an important role in bone remodelling, and tumour necrosis factor related, apoptosis inducing ligand (TRAIL) can induce apoptosis in cancer cells. Their functions are linked by their interactions with osteoprotegerin (OPG).

OBJECTIVE

To investigate the expression of RANKL and TRAIL in a large series of unselected breast cancers and to analyse the relations between these expressions and the expression of OPG, oestrogen receptor, and clinicopathological variables.

METHODS

395 breast cancers were sampled into tissue microarrays and immunohistochemistry undertaken for RANKL and TRAIL.

RESULTS

There was strong expression of RANKL in 14% of the cancers and strong expression of TRAIL in 30%. Expression of RANKL had a negative association with expression of oestrogen receptor (p = 0.036). Expression of TRAIL had a negative association with the Nottingham Prognostic Index (p = 0.021). There was a significant negative relation between expression of RANKL and TRAIL (p<0.005). Unsupervised cluster analysis produced a dendrogram that showed a clear division into two groups, and the expression of oestrogen receptor was significantly higher in one of those groups (p = 0.012).

CONCLUSIONS

There is apparent loss of expression of RANKL in 86% of breast cancers; those tumours that retain expression tend to be oestrogen receptor negative and of a high histological grade. There is strong expression of TRAIL in 30% of breast cancers and these tend to be of better prognostic type. These results may be important in the processes of metastasis to bone and the apoptotic cell death pathway in cancer.

Artificial Neural Network Models for Prediction of Acute Coronary Syndromes Using Clinical Data From the Time of Presentation

STUDY OBJECTIVE

Clinical and ECG data from presentation are highly discriminatory for diagnosis of acute coronary syndromes, whereas definitive diagnosis from serial ECG and cardiac marker protein measurements is usually not available for several hours. Artificial neural networks are computer programs adept at pattern recognition tasks and have been used to analyze data from chest pain patients with a view to developing diagnostic algorithms that might improve triage practices in the emergency department. The aim of this study is to develop and optimize artificial neural network models for diagnosis of acute coronary syndrome, to test these models on data collected prospectively from different centers, and to establish whether the performance of these models was superior to that of models derived using a standard statistical technique, logistic regression.

METHODS

The study used data from 3,147 patients presenting to 3 hospitals with acute chest pain. Data from hospital 1 were used to train the models, which were then tested on independent data from the other 2 hospitals. From 40 potential factors, variables were selected according to the logarithm of their likelihood ratios to produce models using 8, 13, 20, and 40 factors. Identical data were used for logistic regression and artificial neural network models. Calibration and performance were assessed, the latter using receiver operating characteristic (ROC) curve analysis.

RESULTS

Although the performance of artificial neural network models generally increased with increasing numbers of factors, this was insignificant. The 13-factor model was therefore used for the rest of the study owing to its marginally improved calibration over the smallest model. Area under the ROC curve (with standard error) was 0.97 (0.006). The overall sensitivity and specificity of this model for acute coronary syndrome diagnosis using the training data was 0.93. ROC curves for logistic regression and artificial neural network models applied to data from the 3 hospitals were identical. For the 13-factor artificial neural network model tested on data from hospitals 2 and 3, area under the ROC curves (standard error) were 0.93 (0.006) and 0.95 (0.009), respectively. Investigation of the performance of the artificial neural network models throughout the range of predicted probabilities showed that they were well calibrated.

CONCLUSION

This study confirms that artificial neural networks can offer a useful approach for developing diagnostic algorithms for chest pain patients; however, the exceptional performance and simplicity of the logistic model militates in favor of logistic regression for the present task. Our artificial neural network models were well calibrated and performed well on unseen data from different centers. These issues have not been addressed in previous studies. However, and unlike in previous studies, we did not find the performance of artificial neural network models to be significantly different from that of suitably optimized logistic regression models.

Preservation of fertility in women affected by cancer. An audit of the cryopreservation services provided for women at Human Assisted Reproduction Ireland

There has been a remarkable improvement in survival rates for adult and childhood cancers, due to progress in cancer treatments. However multiagent chemotherapy and radiotherapy are associated with gonadal failure. Whereas sperm banking is commonly performed, female gametes are not so amenable to cryopreservation. Options available to women for fertility preservation include, embryo and oocyte cryopreservation. Our unit established an oocyte/embryo cryopreservation service for women affected by cancer in October 2003. Ninteen women have been referred and five (26%) women have had oocytes cryopreserved. The mean age of women in the group cryopreserved was 34 years (range 21-41). Their mean day 3 FSH was 6.2 IU (range 5.5-6.8). The mean dose of rFSH used was 1870 units (range 1500-2600). The mean number of oocytes cryopreserved was 8 (range 3-16). Preservation of fertility is of major concern to women affected by cancer. This service offers them hope for their future fertility.

Identification of patients with evolving coronary syndromes by using statistical models with data from the time of presentation

OBJECTIVE

To derive statistical models for the diagnosis of acute coronary syndromes by using clinical and ECG information at presentation and to assess performance, portability, and calibration of these models, as well as how they may be used with cardiac marker proteins.

DESIGN AND METHODS

Data from 3462 patients in four UK teaching hospitals were used. Inputs for 8, 14, 25, and 43 factor logistic regression models were selected by using log10 likelihood ratios (log10 LRs). Performance was analysed by receiver operating characteristic curves.

RESULTS

A 25 factor model derived from 1253 patients from one centre was selected for further study. On training data, 98.2% of ST elevation myocardial infarctions (STEMIs) and 96.2% of non-ST elevation myocardial infarctions (non-STEMIs) were correctly classified, whereas only 2.1% of non-cardiac cases were incorrectly classified. On data from three other centres, 97.3% of STEMIs and 91.9% of non-STEMIs were correctly classified. Differences in log10 LRs for individual inputs from different centres accounted for the decline in performance when models were applied to unseen data. Classification was improved when output was combined with either clinical opinion or marker proteins.

CONCLUSIONS

Logistic regression models based on data available at presentation can classify patients with chest pain with a high degree of accuracy, particularly when combined with clinical opinion or marker proteins.

The metabolic marker tumour pyruvate kinase type M2 (tumour M2-PK) shows increased expression along the metaplasia-dysplasia-adenocarcinoma sequence in Barrett's oesophagus

BACKGROUND

Proliferating and tumour cells express the glycolytic isoenzyme, pyruvate kinase type M2 (M2-PK). In tumours cells, M2-PK usually exists in dimeric form (tumour M2-PK), causing the accumulation of glycolytic phosphometabolites, which allows cells to invade areas with low oxygen and glucose concentrations.

AIMS

To investigate the expression of tumour M2-PK during the metaplasia-dysplasia-adenocarcinoma sequence of Barrett's oesophagus, and to assess the prognostic usefulness of tumour M2-PK in oesophageal cancer.

MATERIALS/METHODS

One hundred and ninety cases selected from the histopathology archives as follows: 17 reflux oesophagitis, 37 Barrett's oesophagus, 21 high grade dysplasia, 112 adenocarcinomas, and three control tumours. Sections were stained immunohistochemically with antibody to tumour M2-PK.

RESULTS

Tumour M2-PK was expressed in all cases, and increased cytoplasmic expression was seen with progression along the metaplasia-dysplasia-adenocarcinoma sequence. All cases of adenocarcinoma showed 100% staining so that tumour M2-PK was not a useful prognostic marker.

CONCLUSIONS

Tumour M2-PK is not a specific marker of Barrett's adenocarcinoma, but may be important as a marker of transformed and highly proliferating clones during progression along the metaplasia-dysplasia-adenocarcinoma sequence.

Early pregnancy loss: how do men feel?

One in five pregnancies (20%) end in miscarriage. A specialized early pregnancy loss clinic to provide dedicated medical advice and support was established at the Rotunda Hospital in July 2002. A qualitative pilot study was conducted in July 2002 to assess the emotional response of male partners and also to establish if sufficient support services are provided for them. Ten consecutive couples attending the clinic 6-8 weeks following early pregnancy loss were included in the study. The partners were asked to complete a questionnaire with open and closed questions and return in the envelope provided. Nine questionnaires were returned. The average age of men attended was 28.6 years (range 20-39). The feelings described by men were typical of the grief and bereavement process. All wanted more time for discussion with doctors. They felt marginalized and although they felt support services for their partner were adequate, they felt that more support services for male partners should be provided. Based on these research findings, the specialized early pregnancy loss clinic is being developed to partner's needs and expectations. The appointment letter sent to the women now specifically states that the partner is welcome to attend. Partners are now included in the consultation.

The impact of maternal age on pregnancy and its outcome

There were 28,600 deliveries of 500 g or more to women at the Rotunda Hospital between January 1st 1985 and December 1st 1989. Of these, 595 were to women aged 40 years and over. Thirty-five variables of clinical significance were analyzed, comparing those of 40 years of age and more with those under 40. The older group had significant increases in gestational diabetes, ante-partum hemorrhage, fetal distress, prematurity, low birth weight and perinatal mortality. Chromosome congenital abnormalities were significantly higher, particularly Down syndrome. There were significantly increased rates of induction and cesarean section in the older women. Some evidence of interaction of age with other factors was found, however these were difficult to separate out in the clinical setting. We therefore recommend it wiser to manage all elderly gravidas in a high risk manner dealing with cases individually within this framework. Intervention should, however, need to be justified in the older as in the younger woman.

The role of beta-catenin signaling in the malignant potential of cystitis glandularis

PURPOSE

Chronic inflammation is a risk factor for malignant transformation in the bladder. The pro-inflammatory cytokine tumor necrosis factor-alpha (TNFalpha) is a mediator of such inflammation that induces nuclear localization of the adherens junction component beta-catenin. This mechanism has a key role in the initiation and progression of the premalignant lesion Barrett's metaplasia of the esophagus. Cystitis glandularis is a metaplastic lesion of the bladder urothelium occurring in the presence of chronic inflammation and in up to 13% of asymptomatic bladders. Two subtypes are described (typical and intestinal/colonic) with uncertain malignant potential. Etiologically and histologically cystitis glandularis mimics Barrett's metaplasia. We investigated the roles of beta-catenin and TNFalpha in cystitis glandularis.

MATERIALS AND METHODS

Immunohistochemistry and immunofluorescence were used to demonstrate the expression and localization of E-cadherin, beta-catenin and TNFalpha in 9 sections of typical cystitis glandularis and 4 of intestinal/colonic cystitis glandularis. Appropriate controls were used for all experiments.

RESULTS

Immunohistochemistry demonstrated normal membranous expression of E-cadherin and beta-catenin in all cystitis glandularis sections with increased TNFalpha expression. Immunofluorescence showed nuclear localization of beta-catenin in the intestinal/colonic subtype only, which was not observed in typical cystitis glandularis.

CONCLUSIONS

The presence of nuclear beta-catenin suggests that intestinal/colonic cystitis glandularis shares the same signaling pathway with the premalignant lesion Barrett's metaplasia of the esophagus and the intestinal/colonic subtype of cystitis glandularis may have the potential to progress to malignancy. This finding has important implications for the management of this lesion.

A survey of Irish consultants regarding awareness of sperm freezing and assisted reproduction

Chemotherapy and radiotherapy decrease male fertility. Pretreatment semen cryopreservation offers a chance for future fatherhood. However many eligible patients are not referred. One potential reason for the reduced uptake is lack of awareness by referring consultants. We sent a questionnaire to all 41 consultant oncologists, haematologists and urologists listed in the Irish Medical Directory. The questionnaire surveyed the current knowledge, opinions and clinical practices of this key group regarding semen cryopreservation for male cancer patients. 63% responded. 73% routinely discuss semen freezing with their male cancer patients (mostly testicular carcinomas and lymphomas). 100% believe semen cryopreservation helps the patient psychologically. 12% do not know where facilities exist. 92% will only refer men aged between 20 and 40 years. 92% are unaware that semen freezing does not delay cancer treatment. 54% have heard of intracytoplasmic sperm injection (ICSI) but 88% are unaware of its benefits for patients with low sperm counts. Consultants dealing with male cancer patients do not prioritise future fertility. Most of the consultants surveyed were unaware of the advances in reproductive technology and this may be contributing to underutilization of sperm cryopreservation by male cancer patients. Units offering this service need to increase awareness of its potential benefits.

Advancing donor liver age and rapid fibrosis progression following transplantation for hepatitis C

BACKGROUND AND AIM

Cirrhosis with liver failure due to hepatitis C virus (HCV) infection is the most common indication for liver transplantation (LT). Reinfection of the transplanted liver by HCV is inevitable, and aggressive hepatitis with accelerated progression to graft cirrhosis may be observed. Of concern, recent reports suggest that the outcome of LT for HCV may have deteriorated in recent years. Determinants of rate of progression to cirrhosis in the immunocompetent non-transplant patient are well defined, and the most powerful determinant is patient age at the time of infection. Following LT for HCV, recipient age does not affect outcome of HCV reinfection. However, the impact of donor age on graft fibrosis progression rate following LT has not been examined.

METHODS

We have examined post-transplant biopsies to assess histological activity, including fibrosis stage (scored 0-6 units, 6 representing established cirrhosis), and to calculate fibrosis progression rates in 101 post-transplant specimens from 56 HCV infected LT patients. Univariate and multivariate analyses examined the impact of parameters including recipient and donor age and sex on fibrosis progression rate, and on predicted time to cirrhosis.

RESULTS

For the cohort, median fibrosis progression rate was 0.78 units/year, and median interval from transplantation to development of cirrhosis was 7.7 years. In multivariate analysis, donor age (not recipient age) was a powerful determinant (p=0.02) of fibrosis progression rate. When the liver donor was younger than 40 years, median progression rate was 0.6 units/year and interval to cirrhosis was 10 years. When the donor was aged 50 years or more, median progression rate was 2.7 units/year and interval to cirrhosis only 2.2 years. During the observation period there has been a significant increase in donor age (p=0.01) but date of transplantation per se is not a determinant of progression rate when included in multivariate analyses.

CONCLUSIONS

Donor age has a major influence on graft outcome following transplantation for HCV. The changing organ donor profile will affect the long term results of LT for HCV. These observations have important implications for donor liver allocation.

Day 5 inhibin B levels in a treatment cycle are predictive of IVF outcome

BACKGROUND

Day 5 serum inhibin B during IVF treatment has been investigated as a predictor of outcome.

METHODS

A total of 54 women (< or = 39 years, normal menses and endocrine profiles) were treated with urinary gonadotrophins or recombinant FSH following pituitary down-regulation. Serum day 3 FSH in a preceding cycle was <8.5 IU/l. Plasma inhibin B, inhibin A and estradiol were determined after 4 days of gonadotrophin administration (day 5).

RESULTS

Day 5 inhibin B was the most highly correlated with the number of mature follicles (>14 mm), oocytes retrieved and fertilized. Receiver operating characteristic analysis gave high accuracy for day 5 inhibin B in predicting ovarian response and indicated that a threshold of 400 pg/ml may be helpful in the decision as to whether to continue treatment. Women with <400 pg/ml (n = 16) had lower numbers of follicles, mature follicles, oocytes retrieved, fertilized and cleaved compared with those >400 pg/ml (n = 36) and this threshold gave a positive likelihood ratio of 30, 92.9% sensitivity, 95.0% specificity and 86.7% positive predictive value to detect poor ovarian response. Day 5 inhibin B was the best predictor of pregnancy (no live births and four cycles cancelled, low inhibin group; nine live births and no cancelled cycles, high inhibin group).

CONCLUSIONS

Normogonadotrophic, normogonadal women with day 5 inhibin B <400 pg/ml in down-regulated cycles have a poor response to ovarian stimulation and are less likely to conceive compared with women with higher day 5 inhibin B.

Discriminant histological features in the diagnosis of chronic idiopathic inflammatory bowel disease: analysis of a large dataset by a novel data visualisation technique

BACKGROUND/AIMS

The histopathological assessment of endoscopic colorectal biopsies is important in the distinction between normality and chronic idiopathic inflammatory bowel disease, and between ulcerative colitis and Crohn's disease, in subjects with symptoms of bowel dysfunction. This study aims to use carefully defined histopathological observations on a large study population to produce systems that improve classification into these diagnostic categories.

METHODS

Eight hundred and nine endoscopic colorectal biopsies with verified outcomes (165 normal, 473 ulcerative colitis, 171 Crohn's disease) were examined by a single experienced histopathologist and 20 defined features were recorded for each case using a novel graphical interface with reference images of each feature. These features, together with age and sex, were used to produce and test statistical classifiers using logistic regression and a novel growing cell structure technique.

RESULTS

The distinction between chronic idiopathic inflammatory bowel disease and normality was made with a good level of performance by both statistical classifiers (with areas under the receiver operating characteristic curves above 0.80). The growing cell structure system selected features as discriminant that agreed with the published literature. Logistic regression produced a more variable selection of discriminant features because of the high correlation between many features. The distinction between ulcerative colitis and Crohn's disease was performed less accurately, with areas under the receiver operating characteristic curves of about 0.70. Again the features selected as discriminant broadly agreed with those in the published literature.

CONCLUSIONS

Histopathological examination of endoscopic colorectal biopsies is an effective method of distinguishing between subjects with chronic idiopathic inflammatory bowel disease and normality, but less good at distinguishing between ulcerative colitis and Crohn's disease. The features selected as discriminant in this large statistical analysis broadly agree with those published in the literature from more qualitative studies.

Mutations at the mitochondrial DNA polymerase (POLG) locus associated with male infertility

Human mitochondrial DNA polymerase, encoded by POLG, contains a polyglutamine tract encoded by a CAG microsatellite repeat. Analysis of POLG genotypes in different populations identified an association between absence of the common, ten-repeat allele and male infertility typified by a range of sperm quality defects but excluding azoospermia.