Oxidative DNA damage in reconstituting T cells is associated with relapse and inferior survival after allo-SCT.

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is the only curative treatment option for a number of hematologic malignancies. Its therapeutic potential relies on the potency of donor T cells to eliminate residual malignant cells, the so-called graft-versus-leukemia (GVL) effect. Disease relapse remains the most frequent treatment failure and is associated with poor outcome. Therefore, it is inevitable to decipher mechanisms that weaken GVL. In recent years, studies of tumor biology have revealed that metabolic remodeling of the micromilieu can critically regulate immune responses. Accumulation of reactive oxygen species leads to a metabolic condition known as oxidative stress, which can severely hamper T cells. Currently, only a few studies, mainly using preclinical models, have demonstrated the occurrence of oxidative stress after allo-SCTs. Therefore, we sought to investigate oxidative stress in a well-characterized group of patients who underwent allo-SCT and its impact on reconstituting T cells. We identified high concentrations of serum 8-hydroxydeoxyguanosine (8-OHdG) as an established biomarker for oxidative stress. 8-OHdG is one of the major products of DNA oxidation, which is normally rapidly removed. After allo-SCT, T cells accumulated oxidative DNA damage. High cellular 8-OHdG content (8-OHdGhi) was associated not only with signs of enhanced T-cell activation but also premature exhaustion. The inability of 8-OHdGhi T cells to efficiently target malignant cells or produce cytotoxic granzyme B and interferon gamma was associated with a significantly increased relapse risk and a shorter overall survival. Taken together, our novel findings could give reason to focus on bolstering DNA repair in reconstituting T cells as a means to improve GVL efficacy.

Correction: Do multiple experimenters improve the reproducibility of animal studies?

[This corrects the article DOI: 10.1371/journal.pbio.3001564.].

The rearing environment persistently modulates mouse phenotypes from the molecular to the behavioural level.

The phenotype of an organism results from its genotype and the influence of the environment throughout development. Even when using animals of the same genotype, independent studies may test animals of different phenotypes, resulting in poor replicability due to genotype-by-environment interactions. Thus, genetically defined strains of mice may respond differently to experimental treatments depending on their rearing environment. However, the extent of such phenotypic plasticity and its implications for the replicability of research findings have remained unknown. Here, we examined the extent to which common environmental differences between animal facilities modulate the phenotype of genetically homogeneous (inbred) mice. We conducted a comprehensive multicentre study, whereby inbred C57BL/6J mice from a single breeding cohort were allocated to and reared in 5 different animal facilities throughout early life and adolescence, before being transported to a single test laboratory. We found persistent effects of the rearing facility on the composition and heterogeneity of the gut microbial community. These effects were paralleled by persistent differences in body weight and in the behavioural phenotype of the mice. Furthermore, we show that environmental variation among animal facilities is strong enough to influence epigenetic patterns in neurons at the level of chromatin organisation. We detected changes in chromatin organisation in the regulatory regions of genes involved in nucleosome assembly, neuronal differentiation, synaptic plasticity, and regulation of behaviour. Our findings demonstrate that common environmental differences between animal facilities may produce facility-specific phenotypes, from the molecular to the behavioural level. Furthermore, they highlight an important limitation of inferences from single-laboratory studies and thus argue that study designs should take environmental background into account to increase the robustness and replicability of findings.

Do multiple experimenters improve the reproducibility of animal studies?

The credibility of scientific research has been seriously questioned by the widely claimed "reproducibility crisis". In light of this crisis, there is a growing awareness that the rigorous standardisation of experimental conditions may contribute to poor reproducibility of animal studies. Instead, systematic heterogenisation has been proposed as a tool to enhance reproducibility, but a real-life test across multiple independent laboratories is still pending. The aim of this study was therefore to test whether heterogenisation of experimental conditions by using multiple experimenters improves the reproducibility of research findings compared to standardised conditions with only one experimenter. To this end, we replicated the same animal experiment in 3 independent laboratories, each employing both a heterogenised and a standardised design. Whereas in the standardised design, all animals were tested by a single experimenter; in the heterogenised design, 3 different experimenters were involved in testing the animals. In contrast to our expectation, the inclusion of multiple experimenters in the heterogenised design did not improve the reproducibility of the results across the 3 laboratories. Interestingly, however, a variance component analysis indicated that the variation introduced by the different experimenters was not as high as the variation introduced by the laboratories, probably explaining why this heterogenisation strategy did not bring the anticipated success. Even more interestingly, for the majority of outcome measures, the remaining residual variation was identified as an important source of variance accounting for 41% (CI95 [34%, 49%]) to 72% (CI95 [58%, 88%]) of the observed total variance. Despite some uncertainty surrounding the estimated numbers, these findings argue for systematically including biological variation rather than eliminating it in animal studies and call for future research on effective improvement strategies.

Individualized social niches in animals: Theoretical clarifications and processes of niche change.

What are social niches, and how do they arise and change? Our first goal in the present article is to clarify the concept of an individualized social niche and to distinguish it from related concepts, such as a social environment and a social role. We argue that focal individuals are integral parts of individualized social niches and that social interactions with conspecifics are further core elements of social niches. Our second goal in the present article is to characterize three types of processes-social niche construction, conformance, and choice (social NC3 processes)-that explain how individualized social niches originate and change. Our approach brings together studies of behavior, ecology, and evolution and integrates social niches into the broader concept of an individualized ecological niche. We show how clarifying the concept of a social niche and recognizing the differences between the three social NC3 processes enhance and stimulate empirical research.

Social niche shapes social behavior and cortisol concentrations during adolescence in female guinea pigs.

Individualized social niches arise in social groups, resulting in divergent social behavior profiles among group members. During sensitive life phases, the individualized social niche can profoundly impact the development of social behavior and associated phenotypes such as hormone (e.g. cortisol) concentrations. Focusing on adolescence, we investigated the relationship between the individualized social niche, social behavior, and cortisol concentrations (baseline and responsiveness) in female guinea pigs. Females were pair-housed in early adolescence (initial social pair formation), and a social niche transition was induced after six weeks by replacing the partner with either a larger or smaller female. Regarding social behavior, dominance status was associated with aggression in both the initial social pairs and after the social niche transition, and the results suggest that aggression was rapidly and completely reshaped after the social niche transition. Meanwhile, submissive behavior was rapidly reshaped after the social niche transition, but this was incomplete. The dominance status attained in the initial social pair affected the extent of submissive behavior after the social niche transition, and this effect was still detected three weeks after the social niche transition. Regarding cortisol concentrations, higher baseline cortisol concentrations were measured in dominant females in the initial social pairs. After the social niche transition, cortisol responsiveness significantly increased for the females paired with a larger, older female relative to those paired with a smaller, younger female. These findings demonstrate that the social niche during adolescence plays a significant role in shaping behavior and hormone concentrations in females.

Conditional on the social environment? Roots of repeatability in hormone concentrations of male guinea pigs.

Individual differences in behavioral and physiological traits among members of the same species are increasingly being recognized as important in animal research. On the group level, shaping of behavioral and hormonal phenotypes by environmental factors has been reported in different taxa. The extent to which the environment impacts behavior and hormones on the individual level, however, is rather unexplored. Hormonal phenotypes of guinea pigs can be shaped by the social environment on the group level: pair-housed and colony-housed males differ systematically in average testosterone and stressor-induced cortisol levels (i.e. cortisol responsiveness). The aim of the present study was to evaluate whether repeatability and individual variance components (i.e. between- and within-individual variation) of hormonal phenotypes also differ in different social environments. To test this, we determined baseline testosterone, baseline cortisol, and cortisol responsiveness after challenge in same-aged pair-housed and colony-housed guinea pig males over a period of four months. We found comparable repeatability for baseline cortisol and cortisol responsiveness in males from both social conditions. In contrast, baseline testosterone was repeatable only in males from colonies. Interestingly, this result was brought about by significantly larger between-individual variation of testosterone, that was not explained by differences in dominance rank. Individualized social niches differentiated under complex colony, but not pair housing, could be an explanation for this finding.

Repeatability of endocrine traits and dominance rank in female guinea pigs.

BACKGROUND: Glucocorticoids (e.g. cortisol) are associated with variation in social behavior, and previous studies have linked baseline as well as challenge-induced glucocorticoid concentrations to dominance status. It is known that cortisol response to an acute challenge is repeatable and correlates to social behavior in males of many mammal species. However, it is unclear whether these patterns are also consistent for females. The aim of this study was to investigate whether baseline and response cortisol concentrations are repeatable in female guinea pigs (Cavia aperea f. porcellus) and whether dominance rank is stable and correlated to baseline cortisol concentration and/or cortisol responsiveness. RESULTS: Our results show that cortisol responsiveness (after 1 h: R = 0.635, 95% CI = 0.229, 0.927; after 2 h: R = 0.764, 95% CI = 0.433, 0.951) and dominance rank (R = 0.709, 95% CI = 0.316, 0.935) of females were significantly repeatable after six weeks but not correlated. Baseline cortisol was not repeatable (R = 0, 95% CI = 0, 0.690) and also did not correlate to dominance rank. Furthermore, the difference in repeatability estimates of baseline and response values was due to high within-individual variance of baseline cortisol concentration; the amount of between-individual variance was similar for baseline cortisol and the two measures of cortisol responsiveness. CONCLUSIONS: Females occupying different dominance ranks did not have long-term differences in cortisol concentrations, and cortisol responsiveness does not seem to be significantly involved in the maintenance of dominance rank. Overall, this study reveals the remarkable stability of cortisol responsiveness and dominance rank in a female rodent, and it remains an open question whether the magnitude of cortisol responsiveness is adaptive in social contexts for females.

Individuality meets plasticity: Endocrine phenotypes across male dominance rank acquisition in guinea pigs living in a complex social environment.

The time of dominance rank acquisition is a crucial phase in male life history that often affects reproductive success and hence fitness. Hormones such as testosterone and glucocorticoids can influence as well as be affected by this process. At the same time, hormone concentrations can show large individual variation. The extent to which such variation is repeatable, particularly in dynamic social settings, is a question of current interest. The aim of the present study was therefore to investigate how dominance rank and individual differences contribute to variance in hormone concentrations during male rank acquisition in a complex social environment. For this purpose, dominance rank as well as baseline testosterone, baseline cortisol, and cortisol responsiveness after exposure to a novel environment were determined in colony-housed guinea pig males from late adolescence through adulthood. Hormone-dominance relationships and repeatability of hormone measures beyond their relation to rank were assessed. There was a significant positive relationship between baseline testosterone and rank, but this link became weaker with increasing age. Baseline cortisol or cortisol responsiveness, in contrast, were not significantly related to dominance. Notably, all three endocrine parameters were significantly repeatable independent of dominance rank from late adolescence through adulthood. Baseline testosterone and cortisol responsiveness showed a significantly higher repeatability than baseline cortisol. This suggests that testosterone titres and cortisol responsiveness represent stable individual attributes even under complex social conditions.

Right ventricular myocardial infarction in the era of primary percutaneous coronary intervention.

Right ventricular involvement (RVMI) is a relatively frequent complication in patients developing ST-elevation acute myocardial infarction. The initial diagnosis is most often established using electrocardiography or echocardiography. The gold standard among imaging techniques is cardiac magnetic resonance, which allows to distinguish between reversible and irreversible myocardial damage. The key treatment strategy is emergent revascularization by primary percutaneous coronary intervention whereas patients with hypotension and cardiogenic shock due to the RVMI require fluid replacement and catecholamine therapy. In cases where the shock state progresses despite an adequate management, short- or, possibly, long-term mechanical assist device should be implanted either percutaneously or surgically. Despite appreciable advances in the diagnosis and management, RVMI remains an independent predictor of early as well as late complications (Fig. 6, Ref. 62). Keywords: right ventricle myocardial infarction, primary PCI, CMR, mechanical circulatory support, echocardiography.

Adaptive reshaping of the hormonal phenotype after social niche transition in adulthood.

Phenotypic plasticity allows individuals to adjust traits to the environment. Whether long-term adjustments of the phenotype occur during later life stages is largely unknown. To address this question, we examined whether hormonal phenotypes that are shaped by the environment during adolescence can still be reshaped in full adulthood. For this, guinea pig males were either housed in mixed-sex colonies or in heterosexual pairs. In adulthood, males were individually transferred to pair housing with a female. This way, a social niche transition was induced in colony-housed males, but not in pair-housed males. Before transfer, corresponding to findings in adolescence, adult colony-housed males showed significantly higher baseline testosterone levels and lower cortisol responsiveness than pair-housed males. One month after transfer, the hormonal phenotype of colony-housed males was changed towards that of pair-housed males: animals showed comparable baseline testosterone levels and cortisol responsiveness was significantly increased in colony-housed males. This endocrine readjustment builds the basis for an adaptive behavioural tactic in the new social situation. Thus, an adaptive change of the behavioural phenotype may still occur in adulthood via modification of underlying mechanisms. This suggests a greater role for developmental plasticity in later life stages than is commonly presumed.

Isothermal relaxation kinetics for the reduction and oxidation of SrFeO3 based perovskites.

The perovskite oxide SrFeO3 has favourable redox properties for oxygen exchange applications, including oxygen separation and oxygen production chemical looping cycles. For such applications, lower temperature operation can improve the energy demand and feasibility of the process, but can also lead to kinetic limitations. Here we investigate the oxidation and reduction reaction kinetics of SrFeO3 in the temperature range 450-750 K. Isothermal relaxation techniques are used to observe the reaction rates across this temperature range, using a thermogravimetric analysis system. Experimental data are analysed according to an isoconversional method and fit with a simple power law model to extract activation energies. The apparent activation energy of oxidation and reduction was found to be 92 ± 16 and 144 ± 17 kJ mol-1 respectively. Comparison of oxidation and reduction kinetics together with considerations of particle size indicate that the oxidation reaction rate may be limited by diffusion in the bulk, while the reduction reaction rate is limited by the surface reaction. Furthermore, we also investigated the mixed perovskite Sr0.93Ca0.07Fe0.9Co0.1O3, which exhibited a 4-fold increase in the oxidation rate.

Phase transitions in huddling emperor penguins.

Emperor penguins (Aptenodytes forsteri) are highly adapted to the harsh conditions of the Antarctic winter: they are able to fast for up to 134 days during breeding. To conserve energy, emperor penguins form tight groups (huddles), which is key for their reproductive success. The effect of different meteorological factors on the huddling behaviour, however, is not well understood. Using time-lapse image recordings of an emperor penguin colony, we show that huddling can be described as a phase transition from a fluid to a solid state. We use the colony density as order parameter, and an apparent temperature that is perceived by the penguins as the thermodynamic variable. We approximate the apparent temperature as a linear combination of four meteorological parameters: ambient temperature, wind speed, global radiation and relative humidity. We find a wind chill factor of -2.9 °C/(ms -1), a humidity chill factor of -0.5°C/% rel. humidity, and a solar radiation heating factor of 0.3 °C//(Wm 2). In the absence of wind, humidity and solar radiation, the phase transition temperature (50% huddling probability) is -48.2°C for the investigated time period (May 2014). We propose that higher phase transition temperatures indicate a shrinking thermal insulation and thus can serve as a proxy for lower energy reserves of the colony, integrating pre-breeding foraging success at sea and energy expenditure at land due to environmental conditions. As current global change is predicted to have strong detrimental effects on emperor penguins within the next decades, our approach may thus contribute towards an urgently needed long-term monitoring system for assessing colony health.

[Psychosocial interventions in inpatient care : Systematic review of the effectiveness of universal and selective prevention on mental health]. / Psychosoziale Interventionen in der stationären Pflege : Systematische Übersicht des Effekts universeller und selektiver Prävention auf die psychische Gesundheit.

BACKGROUND: There are no sufficient findings from synthesized evidence for the effectiveness of psychosocial interventions to improve mental health in inpatient care. METHODS: A systematic literature search in the databases of MEDLINE, The Cochrane Library, EMBASE, CINAHL, and PsycINFO was carried out, as well as a manual search in Google Scholar and reference lists. Studies which focused on physical or individual activities or therapy or other groups and settings were excluded. The heterogeneity of the studies did not allow meta-analysis. RESULTS: Seven primary studies were included, whose interventions were assigned to the intervention types activation of memories, leisure activities, and social participation. Overall, the quality of studies was rather low. Compared to usual care or the alternative interventions of memory therapy or leisure activities, the positive effects on depressive symptoms, as well as externally assessed and self-reported quality of life or life satisfaction, were not significant. The absence of these measures lead to deterioration of depressive symptoms among residents with dementia. In contrast to memory activation, common leisure activities led to an improvement in wellbeing. One intervention for social participation increased wellbeing and reduced the occurrence of depressive symptoms. CONCLUSION: There is a considerable need for conceptual-theoretical work and research on the effectiveness of psychosocial interventions, particularly for raising participation among persons in inpatient care facilities.

[Cognitive interventions in nursing homes : Systematic review of the preventive effectiveness on cognitive performance in persons in need of care]. / Kognitive Interventionen in Pflegeheimen : Systematische Übersicht der präventiven Wirksamkeit auf die kognitive Leistungsfähigkeit von Pflegebedürftigen.

BACKGROUND: The strengthening of cognitive resources is considered to be a preventive field of action within inpatient care. The aim is to evaluate the effectiveness of such interventions on cognitive performance in nursing home residents. METHODS: A systematic literature search was carried out in the databases MEDLINE, the Cochrane Library, EMBASE, CINAHL and PsycINFO, as well as searches in trial registries and a screening of reference lists. The combined results were based on meta-analyses in random-effects models. RESULTS: By including 10 primary studies, participating in cognitive activities showed a statistically significant greater cognitive performance compared to controls (standardized mean difference SMD = 0.46, 95% confidence interval CI 0.06-0.87, p = 0.0252). Subgroup analyses suggest a superiority of individually oriented cognitive activities with longer training periods and that especially nursing home residents with a better initial level of cognitive performance might benefit from cognitive interventions. However, due to the high risk of bias in the included studies and the presence of substantial heterogeneity, the results must be interpreted with caution. CONCLUSION: The findings imply that cognitive activities implemented in nursing homes might be effective. Considering the low-quality evidence, performance of high-quality studies is essential in order to verify our results.

Activity and safety of crizotinib in patients with advanced clear-cell sarcoma with MET alterations: European Organization for Research and Treatment of Cancer phase II trial 90101 'CREATE'.

BACKGROUND: Clear-cell sarcoma (CCSA) is an orphan malignancy, characterized by a specific t(12;22) translocation, leading to rearrangement of the EWSR1 gene and overexpression of MET. We prospectively investigated the efficacy and safety of the tyrosine kinase inhibitor crizotinib in patients with advanced or metastatic CCSA. PATIENTS AND METHODS: Patients with CCSA received oral crizotinib 250 mg twice daily. Primary end point was objective response rate (ORR), secondary end points included duration of response, disease control rate (DCR), progression-free survival (PFS), progression-free rate (PFR), overall survival (OS), OS rate and safety. The study design focused on MET+ disease with documented rearrangement of the EWSR1 gene by fluorescence in situ hybridization. RESULTS: Among 43 consenting patients with the local diagnosis of CCSA, 36 had centrally confirmed CCSA, 28 of whom were eligible, treated and assessable. Twenty-six out of the 28 patients had MET+ disease, of whom one achieved a confirmed partial response and 17 had stable disease (SD) (ORR 3.8%, 95% confidence interval: 0.1-19.6). Further efficacy end points in MET+ CCSA were DCR: 69.2% (48.2% to 85.7%), median PFS: 131 days (49-235), median OS: 277 days (232-442). The 3-, 6-, 12- and 24-month PFR was 53.8% (34.6-73.0), 26.9% (9.8-43.9), 7.7% (1.3-21.7) and 7.7% (1.3-21.7), respectively. Among two assessable MET- patients, one had stable disease and one had progression. The most common treatment-related adverse events were nausea [18/34 (52.9%)], fatigue [17/34 (50.0%)], vomiting [12/34 (35.3%)], diarrhoea [11/34 (32.4%)], constipation [9/34 (26.5%)] and blurred vision [7/34 (20.6%)]. CONCLUSIONS: The PFS with crizotinib in MET+ CCSA is similar to results achieved first-line in non-selected metastatic soft tissue sarcomas with single-agent doxorubicin. The PFS is similar to results achieved with pazopanib in previously treated sarcoma patients. CLINICAL TRIAL NUMBER: EORTC 90101, EudraCT number 2011-001988-52, NCT01524926.

Implementation of a Clinical Decision Support Tool for Stool Cultures and Parasitological Studies in Hospitalized Patients.

There is substantial evidence that stool culture and parasitological examinations are of minimal to no value after 3 days of hospitalization. We implemented and studied the impact of a clinical decision support tool (CDST) to decrease the number of unnecessary stool cultures (STCUL), ova/parasite (O&P) examinations, and Giardia/Cryptosporidium enzyme immunoassay screens (GC-EIA) performed for patients hospitalized >3 days. We studied the frequency of stool studies ordered before or on day 3 and after day 3 of hospitalization (i.e., categorical orders/total number of orders) before and after this intervention and denoted the numbers and types of microorganisms detected within those time frames. This intervention, which corresponded to a custom-programmed hard-stop alert tool in the Epic hospital information system, allowed providers to override the intervention by calling the laboratory, if testing was deemed medically necessary. Comparative statistics were employed to determine significance, and cost savings were estimated based on our internal costs. Before the intervention, 129/670 (19.25%) O&P examinations, 47/204 (23.04%) GC-EIA, and 249/1,229 (20.26%) STCUL were ordered after 3 days of hospitalization. After the intervention, 46/521 (8.83%) O&P examinations, 27/157 (17.20%) GC-EIA, and 106/1,028 (10.31%) STCUL were ordered after 3 days of hospitalization. The proportions of reductions in the number of tests performed after 3 days and the associated P values were 54.1% for O&P examinations (P < 0.0001), 22.58% for GC-EIA (P = 0.2807), and 49.1% for STCUL (P < 0.0001). This was estimated to have resulted in $8,108.84 of cost savings. The electronic CDST resulted in a substantial reduction in the number of evaluations of stool cultures and the number of parasitological examinations for patients hospitalized for more than 3 days and in a cost savings while retaining the ability of the clinician to obtain these tests if clinically indicated.

Impact of antimicrobial stewardship and rapid microarray testing on patients with Gram-negative bacteremia.

A rapid microarray assay, Nanosphere Verigene® Gram-negative blood culture test (BC-GN), detects four Gram-negative species, four Gram-negative genera, and six resistance genes directly from positive blood culture samples, shortening the time from Gram stain to pathogen and resistance-gene identification. The purpose of this study was to determine the impact of the BC-GN paired with an antimicrobial stewardship intervention on antimicrobial and clinical outcomes. Patients with Gram-negative bacteremia were compared before (n = 456) and after (n = 421) BC-GN implementation. The primary objective was to compare time from Gram stain to antimicrobial switch pre- and post-implementation. Time from Gram stain to effective treatment, in-hospital mortality, and hospital length of stay were also compared. The number and type of antimicrobial switches were similar between groups. Median (IQR) time from Gram stain to antimicrobial switch was significantly decreased in the post group, 28.6 (8.6-56.9) h vs 44.1 (18.9-64.6) h, p = 0.004. In patients on ineffective antimicrobial therapy at the time of result, median time to effective therapy was lower in the post group, 8.8 (5.5-18.4) h vs 24.5 (4.9-44.3) h, p = 0.034. Median (IQR) hospital length of stay was also decreased in the post group, 7 (5-15) days vs 9 (4.5-21) days, p = 0.001. The rate of in-hospital mortality was similar between groups, 11.6% (pre) vs 11.4% (post), p = 0.87. Rapid microarray testing on blood cultures combined with active antimicrobial stewardship intervention was associated with decreased time to antimicrobial switch, time to effective therapy, and hospital length of stay.

Drug-related problems in community-dwelling primary care patients screened positive for dementia.

BACKGROUND: Older people have a higher risk of drug-related problems (DRPs). However, little is known about the prevalence of DRPs in community-dwelling people who screened positive for dementia. Our study aimed to determine (1) the prevalence and types of DRPs and (2) the socio-demographic and clinical variables associated with DRPs in people screened positive for dementia in primary care. METHODS: The Dementia: life- and person-centered help in Mecklenburg-Western Pomerania (DelpHi-MV) study is a general practitioner (GP)-based cluster-randomized controlled intervention study to implement and evaluate an innovative concept of collaborative dementia care management in the primary care setting in Germany. Medication reviews of 446 study participants were conducted by pharmacists based on a comprehensive baseline assessment that included a computer-based home medication assessment. ClinicalTrials.gov Identifier: NCT01401582. RESULTS: A total of 1,077 DRPs were documented. In 414 study participants (93%), at least one DRP was detected by a pharmacist. The most frequent DRPs were administration and compliance problems (60%), drug interactions (17%), and problems with inappropriate drug choice (15%). The number of DRPs was significantly associated with the total number of drugs taken and with a formal diagnosis of a mental or behavioral disorder. CONCLUSIONS: Degree of cognitive impairment (MMSE defined) and formal diagnosis of dementia were not risk factors for an increased number of DRPs. However, the total number of drug taken and the presence of a diagnosis of mental and behavioral disorders were associated with an increased total number of DRPs.