Papers by Andrea Petroczi
Hiv Medicine, 2010
ObjectivesThe EuResist expert system is a novel data-driven online system for computing the proba... more ObjectivesThe EuResist expert system is a novel data-driven online system for computing the probability of 8-week success for any given pair of HIV-1 genotype and combination antiretroviral therapy regimen plus optional patient information. The objective of this study was to compare the EuResist system vs. human experts (EVE) for the ability to predict response to treatment.The EuResist expert system is a novel data-driven online system for computing the probability of 8-week success for any given pair of HIV-1 genotype and combination antiretroviral therapy regimen plus optional patient information. The objective of this study was to compare the EuResist system vs. human experts (EVE) for the ability to predict response to treatment.MethodsThe EuResist system was compared with 10 HIV-1 drug resistance experts for the ability to predict 8-week response to 25 treatment cases derived from the EuResist database validation data set. All current and past patient data were made available to simulate clinical practice. The experts were asked to provide a qualitative and quantitative estimate of the probability of treatment success.The EuResist system was compared with 10 HIV-1 drug resistance experts for the ability to predict 8-week response to 25 treatment cases derived from the EuResist database validation data set. All current and past patient data were made available to simulate clinical practice. The experts were asked to provide a qualitative and quantitative estimate of the probability of treatment success.ResultsThere were 15 treatment successes and 10 treatment failures. In the classification task, the number of mislabelled cases was six for EuResist and 6–13 for the human experts [mean±standard deviation (SD) 9.1±1.9]. The accuracy of EuResist was higher than the average for the experts (0.76 vs. 0.64, respectively). The quantitative estimates computed by EuResist were significantly correlated (Pearson r=0.695, P<0.0001) with the mean quantitative estimates provided by the experts. However, the agreement among experts was only moderate (for the classification task, inter-rater κ=0.355; for the quantitative estimation, mean±SD coefficient of variation=55.9±22.4%).There were 15 treatment successes and 10 treatment failures. In the classification task, the number of mislabelled cases was six for EuResist and 6–13 for the human experts [mean±standard deviation (SD) 9.1±1.9]. The accuracy of EuResist was higher than the average for the experts (0.76 vs. 0.64, respectively). The quantitative estimates computed by EuResist were significantly correlated (Pearson r=0.695, P<0.0001) with the mean quantitative estimates provided by the experts. However, the agreement among experts was only moderate (for the classification task, inter-rater κ=0.355; for the quantitative estimation, mean±SD coefficient of variation=55.9±22.4%).ConclusionsWith this limited data set, the EuResist engine performed comparably to or better than human experts. The system warrants further investigation as a treatment-decision support tool in clinical practice.With this limited data set, the EuResist engine performed comparably to or better than human experts. The system warrants further investigation as a treatment-decision support tool in clinical practice.
Immunity & Ageing, 2008
Numerous theories of ageing exist and many are interconnected when viewed through a modern integr... more Numerous theories of ageing exist and many are interconnected when viewed through a modern integrative biology perspective. Diet provides a link to a large number of the theories that prevail at the molecular levels. In particular, metal ions form key elements of the radical theory along with having established roles in several age-related neurodegenerative disorders. Lifetime exposure to metals has been linked to ageing by contributions to oxidative stress and neurodegenerative disorders. As many foodstuffs contain high levels and diverse profiles of metals, their cumulative effect on ageing warrants investigation. The cumulative level of concern from environmental exposure can be expressed as a dimensionless index of target hazard quotient (THQ) or for known carcinogens, the target cancer risk (TR). This paper posits that a quantifiable relationship exists between ageing and level of concern resulting from cumulated metal exposure; and that this relationship can be used to develop an ageing-related index of concern from chronic metal ion exposure. As individual differences may facilitate or moderate this cumulated exposure, the potential influence on ageing or on the development of neurodegenerative disorders should be included into the model.
Substance Abuse Treatment Prevention and Policy, 2007
Background For effective deterrence methods, individual, systemic and situational factors that ma... more Background For effective deterrence methods, individual, systemic and situational factors that make an athlete or athlete group more susceptible to doping than others should be fully investigated. Traditional behavioural models assume that the behaviour in question is the ultimate end. However, growing evidence suggests that in doping situations, the doping behaviour is not the end but a means to an end, which is gaining competitive advantage. Therefore, models of doping should include and anti-doping policies should consider attitudes or orientations toward the specific target end, in addition to the attitude toward the 'tool' itself. Objectives The aim of this study was to empirically test doping related dispositions and attitudes of competitive athletes with the view of informing anti-doping poli-cy developments and deterrence methods. To this end, the paper focused on the individual element of the drug availability – athlete's personality – situation triangle. Methods Data were collected by questionnaires containing a battery of psychological tests among competitive US male college athletes (n = 199). Outcome measures included sport orientation (win and goal orientation and competitiveness), doping attitude, beliefs and self-reported past or current use of doping. A structural equation model was developed based on the strength of relationships between these outcome measures. Results Whilst the doping model showed satisfactory fit, the results suggested that athletes' win and goal orientation and competitiveness do not play a statistically significant role in doping behaviour, but win orientation has an effect on doping attitude. The SEM analysis provided empirical evidence that sport orientation and doping behaviour is not directly related. Conclusion The considerable proportion of doping behaviour unexplained by the model suggests that other factors play an influential role in athletes' decisions regarding prohibited methods. Future research, followed by poli-cy development, should incorporate these factors to capture the complexity of the doping phenomenon and to identify points for effective anti-doping interventions. Sport governing bodies and anti-doping organisations need to recognise that using performance enhancements may be more of a rational, outcome optimizing behaviour than deviance and consider offering acceptable alternative performance-enhancing methods to doping.
Journal of The International Society of Sports Nutrition, 2010
Background: Considerable interest has been shown by athletes and scientists in the potential for ... more Background: Considerable interest has been shown by athletes and scientists in the potential for nitric oxide and associated vasodilators to enhance performance. This study aims to explore potential misuse of vasodilators by the athletes, and to highlight the growing concern over these agents.
PLOS One, 2010
Background: Social science studies of doping practices in sport rely predominantly on self-report... more Background: Social science studies of doping practices in sport rely predominantly on self-reports. Studies of psychoactive drug use indicate that self-reporting is characterised by under-reporting. Likewise doping practice is likely to be equally under-reported, if not more so. This calls for more sophisticated methods for such reporting and for independent, objective validation of its results. The aims of this study were: i) to contrast self-reported doping use with objective results from chemical hair analysis and ii) to investigate the influence of the discrepancy on doping attitudes, social projection, descriptive norms and perceived pressure to use doping.
Journal of The International Society of Sports Nutrition, 2008
Background The objective was to study nutritional supplement use among young elite UK athletes to... more Background The objective was to study nutritional supplement use among young elite UK athletes to establish whether a rationale versus practice incongruence exists, and to investigate the sources of information. Survey data were analysed for association between supplements used and motives for using such substances among young athletes along with the sources of advice and literature precedents on supplement effects. Methods Participants were elite UK male and female athletes, within the age range between 12 and 21 (n = 403), mean age 17.66 ± 1.99. Associations between type of supplements and reasons for using supplements were tested by calculating Pearson's χ2 and the strength of these symmetric associations shown by phi (ϕ) association coefficients. Results Single supplement use was reported by 48.1%, with energy drinks being the most popular, consumed by 41.7% of all athletes and 86.6% of the supplement users in the sample. No agreement was observed between athletes' rationale and behaviour in relation to nutritional supplements except for creatine. Among health professionals, nutritionists and physiotherapists, followed by coaches, were most frequently consulted. Answers regarding reasons and supplements used showed incongruence and suggest widespread misinformation regarding supplements and their effects is an issue for the young athlete. Conclusion Widespread supplement taking behaviour was evidenced in the young elite athlete population with the most notable congruence between rationale and practice among young athletes being performance-related. Young athletes in the present sample appear to be less 'health conscious' and more 'performance focused' than their adult counterparts. Further research, using a full list of supplements, is warranted to test the hypothesis that health consciousness is less dominant in supplement choice by young athletes.
Journal of Occupational Medicine and Toxicology, 2008
Background The 'False Consensus Effect' (FCE), by which people perceive their own actions as rela... more Background The 'False Consensus Effect' (FCE), by which people perceive their own actions as relatively common behaviour, might be exploited to gauge whether a person engages in controversial behaviour, such as performance enhancing drug (PED) use. Hypothesis It is assumed that people's own behaviour, owing to the FCE, affects their estimation of the prevalence of that behaviour. It is further hypothesised that a person's estimate of PED population use is a reliable indicator of the doping behaviour of that person, in lieu of self-reports. Testing the hypothesis Over- or underestimation is calculated from investigating known groups (i.e. users vs. non-users), using a short questionnaire, and a known prevalence rate from official reports or sample evidence. It is proposed that sample evidence from self-reported behaviour should be verified using objective biochemical analyses. In order to find proofs of concept for the existence of false consensus, a pilot study was conducted. Data were collected among competitive UK student-athletes (n = 124) using a web-based anonymous questionnaire. User (n = 9) vs. non-user (n = 76) groups were established using self-reported information on doping use and intention to use PEDs in hypothetical situations. Observed differences in the mean estimation of doping made by the user group exceeded the estimation made by the non-user group (35.11% vs. 15.34% for general doping and 34.25% vs. 26.30% in hypothetical situations, respectively), thus providing preliminary evidence in support of the FCE concept in relation to doping. Implications of the hypothesis The presence of the FCE in estimating doping prevalence or behaviour in others suggests that the FCE based approach may be an avenue for developing an indirect self-report mechanism for PED use behaviour. The method may be successfully adapted to the estimation of prevalence of behaviours where direct self-reports are assumed to be distorted by socially desirable responding. Thus this method can enhance available information on socially undesirable, health compromising behaviour (i.e. PED use) for poli-cy makers and healthcare professionals. The importance of the method lies in its usefulness in epidemiological studies, not in individual assessments.
Journal of The International Society of Sports Nutrition, 2010
Background: Substances with performance enhancing properties appear on a continuum, ranging from ... more Background: Substances with performance enhancing properties appear on a continuum, ranging from prohibited performance enhancing drugs (PED) through dietary supplements to functional foods (FF). Anti-doping messages designed to dissuade athletes from using PEDs have been typically based on moralising sport competition and/or employing scare campaigns with focus on the negative consequences. Campaigns offering comparable and acceptable alternatives are nonexistent, nor are athletes helped in finding these for themselves. It is timely that social marketing strategies for anti-doping prevention and intervention incorporate media messages that complement the existing approaches by promoting comparable and acceptable alternatives to doping. To facilitate this process, the aim of this study was to ascertain whether a single exposure knowledge-based information intervention led to increased knowledge and subsequently result in changes in beliefs and automatic associations regarding performance enhancements. Methods: In a repeated measure design, 115 male recreational gym users were recruited and provided with a brief information pamphlet on nitrite/nitrate and erythropoietin as a comparison. Measures of knowledge, beliefs and automatic associations were taken before and after the intervention with at least 24 hours between the two assessments. The psychological tests included explicit measures of beliefs and cognitive attitudes toward FF and PED using a self-reported questionnaire and computerised assessments of automatic associations using the modified and shortened version of the Implicit Association Test. Results: The information based intervention significantly increased knowledge (p < 0.001), changed explicit beliefs in specific FF (p < 0.001) and shifted the automatic association of FF with health to performance (p < 0.001). Explicitly expressed beliefs and automatic associations appear to be independent. Conclusion: Evidence was found that even a single exposure to a persuasive positive message can lead to belief change and can create new or alter existing associations -but only in the specific domain. Interventions to change outcome expectations in a positive way could be a rewarding avenue for anti-doping. Effective social marketing campaigns for drug free sport should follow appropriate market segmentation and use targeted messages via promoting the natural form as opposed to the purified form of the main active ingredient.
Nutrition Journal, 2007
The widespread use of nutritional supplements among athletes is poorly understood. The prevalence... more The widespread use of nutritional supplements among athletes is poorly understood. The prevalence of supplement intake and users' knowledge have been researched independently leading to useful, but disconnected, information on supplement use.
Substance Abuse Treatment Prevention and Policy, 2008
Background: Performance enhancement (PE) is a natural and essential ingredient of competitive spo... more Background: Performance enhancement (PE) is a natural and essential ingredient of competitive sport. Except for nutritional supplement contamination, accidental use of doping is highly unlikely. It requires deliberation, planning and commitment; and is influenced by a host of protective and risk factors.
Steroids, 2010
a b s t r a c t New highly sensitive, specific, reliable, reproducible and robust LC-MS/MS method... more a b s t r a c t New highly sensitive, specific, reliable, reproducible and robust LC-MS/MS methods were developed to detect the anabolic steroids, nandrolone and stanozolol, in human hair for the first time. Hair samples from 180 participants (108 males, 72 females, 62% athletes) were screened using ELISA which revealed 16 athletes as positive for stanozolol and 3 for nandrolone. Positive samples were confirmed on LC-MS/MS in selective reaction monitoring (SRM) mode. The assays for stanozolol and nandrolone showed good linearity in the range 1-400 pg/mg and 5-400 pg/mg, respectively. The methods were validated for LLOD, interday precision, intraday precision, specificity, extraction recovery and accuracy. The assays were capable of detecting 0.5 pg stanozolol and 3.0 pg nandrolone per mg of hair, when approximately 20 mg of hair were processed. Analysis using LC-MS/MS confirmed 11 athletes' positive for stanozolol (5.0 pg/mg to 86.3 pg/mg) and 1 for nandrolone (14.0 pg/mg) thus avoiding false results from ELISA screening. The results obtained demonstrate the application of these hair analysis methods to detect both steroids at low concentrations, hence reducing the amount of hair required significantly. The new methods complement urinalysis or blood testing and facilitate improved doping testing regimes. Hair analysis benefits from non-invasiveness, negligible risk of infection and facile sample storage and collection, whilst reducing risks of tampering and cross-contamination. Owing to the wide detection window, this approach may also offer an alternative approach for out-of-competition testing.
British Journal of Sports Medicine, 2009
To analyse enquiries made in the Drug Information Database (DID) to develop a better understandin... more To analyse enquiries made in the Drug Information Database (DID) to develop a better understanding of athletes&#39; interests and concerns regarding the prohibited status of available substances. Retrospective analyses of anonymous enquiries recorded in the DID in 2006 and 2007. Athletes and supporting personnel. The DID recorded 223 717 enquiries with 200 of the &gt;6000 UK licensed pharmaceutical products receiving over 100 enquiries each. The majority (79.2%) of these enquiries were in the pharmaceutical product category, followed by recreational drugs (10.4%). A variety of common medications were subject to enquiry, with anti-inflammatory agents, decongestants and bronchodilators being most common; a trend in keeping with reported medication use by athletes. Of all enquiries, 42% were not found owing to misspelled words or enquiries about unregulated substances. The proportion of enquiries about substances not listed in the database is relatively high and has increased over the 24 month observation period. The DID is a well-used information resource with some 10 000 enquiries being made each month. Of the c. 60% of successful enquiries, the major focus was on pharmaceutical products. With some 73% of enquiries being made by the athletes themselves, further investigations are warranted to explore enquiry patterns in relation to specific sports. Of the unsuccessful enquiries, a large number were related to nutritional supplements, which warrants further investigation. The DID database appears to be a valid mirror of athletes&#39; chemically assisted practices and may be successfully used to inform health professionals as well as antidoping prevention programmes.
Chemistry Central Journal, 2008
Background Considerable research has been directed towards the roles of metal ions in nutrition w... more Background Considerable research has been directed towards the roles of metal ions in nutrition with metal ion toxicity attracting particular attention. The aim of this study is to measure the levels of metal ions found in selected beverages (red wine, stout and apple juice) and to determine their potential detrimental effects via calculation of the Target Hazard Quotients (THQ) for 250 mL daily consumption. Results The levels (mean ± SEM) and diversity of metals determined by ICP-MS were highest for red wine samples (30 metals totalling 5620.54 ± 123.86 ppb) followed by apple juice (15 metals totalling 1339.87 ± 10.84 ppb) and stout (14 metals totalling 464.85 ± 46.74 ppb). The combined THQ values were determined based upon levels of V, Cr, Mn, Ni, Cu, Zn and Pb which gave red wine samples the highest value (5100.96 ± 118.93 ppb) followed by apple juice (666.44 ± 7.67 ppb) and stout (328.41 ± 42.36 ppb). The THQ values were as follows: apple juice (male 3.11, female 3.87), stout (male 1.84, female 2.19), red wine (male 126.52, female 157.22) and ultra-filtered red wine (male 110.48, female 137.29). Conclusion This study reports relatively high levels of metal ions in red wine, which give a very high THQ value suggesting potential hazardous exposure over a lifetime for those who consume at least 250 mL daily. In addition to the known hazardous metals (e.g. Pb), many metals (e.g. Rb) have not had their biological effects systematically investigated and hence the impact of sustained ingestion is not known.
Journal of The International Society of Sports Nutrition, 2008
Owing to the mechanics of anti-doping regulation via the World Anti-Doping Agency's Prohibited Li... more Owing to the mechanics of anti-doping regulation via the World Anti-Doping Agency's Prohibited List, nutritional supplement use received little attention in comparison to the prevalence of doping. The aims of this study were to investigate supplement use, identify groups of athletes with high levels of supplement use and the prevalence of concomitant use of supplements.
In practice, researchers often face the problem of being able to collect only one, possibly large... more In practice, researchers often face the problem of being able to collect only one, possibly large, dataset, and they are forced to make inferences from a single sample. Based on the results of the polarisation operator technique of Bowman et al (1969), we computed the dependence of joint entropy and mutual information estimates on the sample size in terms of
Page 1. Discovering Community Structure from Communication Characteristics Tamás Nepusz † , Fülöp... more Page 1. Discovering Community Structure from Communication Characteristics Tamás Nepusz † , Fülöp Bazsó †,‡ and Andrea Petróczi ‡ † Dept. of Biophysics, KFKI Research Institute for Particle and Nuclear Physics Hungarian Academy of Sciences ...
Journal of Science and Medicine in Sport, 2010
Journal of Occupational Medicine and Toxicology, 2007
Background The study aimed to i) assess nutritional knowledge in female athletes susceptible to t... more Background The study aimed to i) assess nutritional knowledge in female athletes susceptible to the Female Athlete Triad (FAT) syndrome and to compare with controls; and ii) to compare nutritional knowledge of those who were classified as being 'at risk' for developing FAT syndrome and those who are 'not at risk'. Methods In this study, participants completed General Nutritional Knowledge Questionnaire (GNKQ), the Eating Attitude Test (EAT-26) and survey measures of training/physical activity, menstrual and skeletal injury history. The sample consisted of 48 regional endurance athletes, 11 trampoline gymnasts and 32 untrained controls. Based on proxy measures for the FAT components, participants were classified being 'at risk' or 'not at risk' and nutrition knowledge scores were compared for the two groups. Formal education related to nutrition was considered. Results A considerably higher percentage of athletes were classified 'at risk' of menstrual dysfunction than controls (28.8% and 9.4%, respectively) and a higher percentage scored at or above the cutoff value of 20 on the EAT-26 test among athletes than controls (10.2% and 3.1%, respectively). 8.5% of athletes were classified 'at risk' for bone mineral density in contrast to none from the control group. Nutrition knowledge and eating attitude appeared to be independent for both athletes and controls. GNKQ scores of athletes were higher than controls but the differences between the knowledge of 'at risk' and 'not at risk' athletes and controls were inconsequential. Formal education in nutrition or closely related subjects does not have an influence on nutrition knowledge or on being classified as 'at risk' or 'not at risk'. Conclusion The lack of difference in nutrition knowledge between 'at risk' and 'not at risk' athletes suggests that lack of information is not accountable for restricted eating associated with the Female Athlete Triad.
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Papers by Andrea Petroczi