ß2-adrenoceptor agonists and antagonists and risk of Parkinson's disease.

BACKGROUND: ß2-adrenoreceptors have recently been identified as regulators of the α-synuclein gene, which is implicated in the pathogenesis of Parkinson's disease. OBJECTIVE: The objectives of this study were to assess the association between use of ß2-agonists and ß-antagonists and the risk of developing PD. METHODS: We conducted a nested case-control study in a cohort of 1,762,164 adults without a diagnosis of PD. They were identified on January, 1, 2004, from the electronic medical records of the largest health care provider in Israel. Participants were followed up until June 30, 2017, for the occurrence of PD. Ten randomly selected controls were matched to each case of PD on age, sex, ethnic group, and duration of follow-up. RESULTS: During follow-up 11,314 patients were newly diagnosed with PD and were matched with 113,140 controls. An increased risk of PD was seen with the use of nonselective ß-antagonists (RR, 2.04 [1.90-2.20]) but not with the use of selective ß1-antagonists (RR, 1.00 [0.95-1.05]). Use of ß2-agonists was associated with reduced risk of PD (RR, 0.89 [0.82-0.96] for short-acting; RR, 0.84 [0.76-0.93] for long-acting; and RR, 0.49 [0.25-0.92] for ultra-long-acting ß2-agonists). In an analysis of individual drugs, propranolol and salbutamol were significantly associated with PD risk, even when these drugs were ascertained 5 years prior to the index date, compared with nonusers (RR, 1.31 [1.08-1.58] and 1.89 {1.53-2.33]) in patients who filled <6 and ≥6 propranolol prescriptions, respectively; the corresponding RRs for salbutamol were 0.95 (0.83-1.08) and 0.65 (0.45-0.94), respectively. CONCLUSIONS: Use of propranolol appears to be associated with an increased risk of PD, whereas use of ß2-agonists is associated with a decreased risk of PD. © 2018 International Parkinson and Movement Disorder Society.

Systems pharmacology to predict drug toxicity: integration across levels of biological organization.

To achieve sensitive and specific mechanism-based prediction of drug toxicity, the tools of systems pharmacology will be integrated using structured ontological approaches, analytics, mathematics, and statistics. Success of this effort is based on the assumption that a systems network that consists of drug-induced perturbations of physiological functions can be characterized. This network spans the hierarchy of biological organization, from gene to mRNA to protein to intracellular organelle to cell to organ to organism. It is populated with data from each of these levels of biological organization. These data, from disparate sources, include the published literature, drug development archives of all approved drugs and drug candidates that did not complete development, and various toxicity databases and adverse event reporting systems. The network contains interrelated genomics, transcriptomics, and metabolomics data, as well as organ and physiological functional data that are derived from the universe of information that describes and analyzes drug toxicity. Here we describe advances in bioinformatics, computer sciences, next-generation sequencing, and systems biology that create the opportunity for integrated systems pharmacology-based prediction of drug safety.

Logic-Based and Cellular Pharmacodynamic Modeling of Bortezomib Responses in U266 Human Myeloma Cells.

Systems models of biological networks show promise for informing drug target selection/qualification, identifying lead compounds and factors regulating disease progression, rationalizing combinatorial regimens, and explaining sources of intersubject variability and adverse drug reactions. However, most models of biological systems are qualitative and are not easily coupled with dynamical models of drug exposure-response relationships. In this proof-of-concept study, logic-based modeling of signal transduction pathways in U266 multiple myeloma (MM) cells is used to guide the development of a simple dynamical model linking bortezomib exposure to cellular outcomes. Bortezomib is a commonly used first-line agent in MM treatment; however, knowledge of the signal transduction pathways regulating bortezomib-mediated cell cytotoxicity is incomplete. A Boolean network model of 66 nodes was constructed that includes major survival and apoptotic pathways and was updated using responses to several chemical probes. Simulated responses to bortezomib were in good agreement with experimental data, and a reduction algorithm was used to identify key signaling proteins. Bortezomib-mediated apoptosis was not associated with suppression of nuclear factor κB (NFκB) protein inhibition in this cell line, which contradicts a major hypothesis of bortezomib pharmacodynamics. A pharmacodynamic model was developed that included three critical proteins (phospho-NFκB, BclxL, and cleaved poly (ADP ribose) polymerase). Model-fitted protein dynamics and cell proliferation profiles agreed with experimental data, and the model-predicted IC50 (3.5 nM) is comparable to the experimental value (1.5 nM). The cell-based pharmacodynamic model successfully links bortezomib exposure to MM cellular proliferation via protein dynamics, and this model may show utility in exploring bortezomib-based combination regimens.

Effects of the physical work environment on physiological measures of stress.

AIMS: In this study we investigated the effects of the physical work environment on two physiological measures of the stress response. METHODS AND RESULTS: Circadian variations in vagally mediated heart rate variability (HRV) and the morning rise in cortisol were evaluated in 60 participants working in a government building either in a traditional (individual offices and old cubicles; n=40) or a modern workspace (individualized cubicles with improved views and lighting; n=20). Results revealed significant linear (B=-1.03; confidence interval: -1.05 to -1.01, P<0.05) and quadratic (B=1.001; confidence interval: 1.0004-1.002, P<0.05) trends by office type interactions for indices of vagally mediated HRV. Individuals in the old office space had flatter slopes and thus less circadian variation including less HRV at night, and a larger rise in cortisol upon awakening compared with those in the new office space. CONCLUSION: These results indicate that physical features of the work environment may affect two aspects of the physiological stress response: circadian variations in HRV and the morning rise in cortisol. These findings have important social, economic, and public health implications for work environment risk factors on health.

Metal impurities in food and drugs.

The major metals of potential health concern found in food, drugs (medicines), and dietary supplements are lead, cadmium, mercury, and arsenic. Other metals, such as chromium, copper, manganese, molybdenum, vanadium, nickel, osmium, rhodium, ruthenium, iridium, palladium, and platinum, may be used or introduced during manufacturing and may be controlled in the final article as impurities. Screening for metals in medicines and dietary supplements rarely indicates the presence of toxic metal impurities at levels of concern. The setting of heavy metal limits is appropriate for medicines and is appropriate for supplements when heavy metals are likely or certain to contaminate a given product. Setting reasonable health-based limits for some of these metals is challenging because of their ubiquity in the environment, limitations of current analytical procedures, and other factors. Taken together, compendial tests for metals in food and drugs present an array of issues that challenge compendial scientists.

A pilot randomized clinical trial utilizing the drug burden index to reduce exposure to anticholinergic and sedative medications in older people.

BACKGROUND: The drug burden index (DBI) is an evidence-based tool that utilizes pharmacologic principles to calculate an individual's total exposure to anticholinergic and sedative medications. Higher DBI has been associated with functional impairment in observational studies of older people. OBJECTIVE: To assess the impact of providing information about DBI to general practitioners (GPs) on prescribing for older people. METHODS: This was a cluster randomized controlled trial with 3 months of follow-up. Participants were volunteers aged ≥70 years, living in self-care retirement villages in Sydney, Australia. The study intervention involved a letter and phone call to GPs, using DBI to prompt them to consider cessation or dose reduction of anticholinergic and sedative medications. The primary study outcome was to assess the impact of information about DBI on prescribing practices of the GPs. RESULTS: A total of 115 participants were enrolled, 57 in the intervention group (from 6 sites) and 58 in the control group (from 6 sites). At baseline, 19 of 57 participants in the intervention group and 31 of 58 participants in the control group had a DBI >0 (p < 0.05). At follow-up, a DBI change was observed in 16 participants. DBI decreased in 12 participants, 6 (32%) in the intervention group, and 6 (19%) in the control group. GPs identified the following barriers to reducing anticholinergic and sedative drugs: uncomfortable altering prescriptions initiated by specialists; unable to influence patients' attitudes; unaware of patients' medications and strong clinical indication. CONCLUSIONS: The intervention targeting GPs' prescribing practices was less effective than anticipated in reducing anticholinergic and sedative drug exposure, and barriers were identified. Future studies should explore multidisciplinary interventions, engaging patients, specialists, GPs, and pharmacists.

Total Protein Methods and Their Potential Utility to Reduce the Risk of Food Protein Adulteration.

Kjeldahl and combustion (Dumas) methods are widely accepted for total protein determination but lack analytical selectivity for protein because they measure protein on the basis of sample nitrogen content. Adulteration incidents exploiting this analytical vulnerability (for example, melamine) demonstrate that these methods are no longer sufficient to protect the public health. This article explores the challenges and opportunities to move beyond total nitrogen based methods for total protein measurement. First, it explores the early history of protein measurement science, complexities of current global protein measurement activities, and ideal analytical performance characteristics for new methods. Second, it comprehensively reviews the pros and cons of current and emerging approaches for protein measurement, including their selectivity for protein, ability to detect adulteration, and practicality for routine use throughout the supply chain. It concludes that some existing highly selective methods for food protein measurement have potential for routine quality control. It also concludes that their successful implementation will require matrix-specific validation and the use of supporting reference materials. These methods may be suitable only for food ingredients that have a low degree of compositional variability and are not complex finished food products.

Stereochemistry of an agonist determines coupling preference of beta2-adrenoceptor to different G proteins in cardiomyocytes.

A fundamental question regarding receptor-G protein interaction is whether different agonists can lead a receptor to different intracellular signaling pathways. Our previous studies have demonstrated that although most beta(2)-adrenoceptor agonists activate both G(s) and G(i) proteins, fenoterol, a full agonist of beta(2)-adrenoceptor, selectively activates G(s) protein. Fenoterol contains two chiral centers and may exist as four stereoisomers. We have synthesized a series of stereoisomers of fenoterol and its derivatives and characterized their receptor binding and pharmacological properties. We tested the hypothesis that the stereochemistry of an agonist determines selectivity of receptor coupling to different G protein(s). We found that the R,R isomers of fenoterol and methoxyfenoterol exhibited more potent effects to increase cardiomyocyte contraction than their S,R isomers. It is noteworthy that although (R,R)-fenoterol and (R,R)-methoxyfenoterol preferentially activate G(s) signaling, their S,R isomers were able to activate both G(s) and G(i) proteins as evidenced by the robust pertussis toxin sensitivities of their effects on cardiomyocyte contraction and on phosphorylation of extracellular signal-regulated kinase 1/2. The differential G protein selectivities of the fenoterol stereoisomers were further confirmed by photoaffinity labeling studies on G(s),G(i2), and G(i3) proteins. The inefficient G(i) signaling with the R,R isomers is not caused by the inability of the R,R isomers to trigger the protein kinase A (PKA)-mediated phosphorylation of the beta(2)-adrenoceptor, because the R,R isomers also markedly increased phosphorylation of the receptor at serine 262 by PKA. We conclude that in addition to receptor subtype and phosphorylation status, the stereochemistry of a given agonist plays an important role in determining receptor-G protein selectivity and downstream signaling events.

Drug Burden Index and physical function in older Australian men.

AIMS: This study evaluated the associations of physical performance and functional status measures with the Drug Burden Index in older Australian men. The Drug Burden Index is a measure of total exposure to anticholinergic and sedative medications that incorporates the principles of dose-response and maximal effect. METHODS: A cross-sectional survey was performed on community-dwelling older men enrolled in The Concord Health and Ageing in Men Project, Sydney, Australia. Outcomes included chair stands, walking speed over 6 m, 20-cm narrow walk speed, balance, grip strength and Instrumental Activities of Daily Living score (IADLs). RESULTS: The study population consisted of 1705 men (age 76.9 +/- 5.5 years). Of the 1527 (90%) participants who reported taking medications, 21% were exposed to anticholinergic and 13% to sedative drugs. The average Drug Burden Index in the study population was 0.18 +/- 0.35. After adjusting for confounders (sociodemographics, comorbidities, cognitive impairment, depression), Drug Burden Index was associated with slower walking speed (P < 0.05), slower narrow walk speed (P < 0.05), balance difficulty (P < 0.01), grip weakness (P < 0.01) and poorer performance on IADLs (P < 0.05). Associations with physical performance and function were stronger for the sedative than for the anticholinergic component of the Drug Burden Index. CONCLUSIONS: Higher Drug Burden Index is associated with poorer physical performance and functional status in community-dwelling older Australian men. The Drug Burden Index has broad applicability as a tool for assessing the impact of medications on functions that determine independence in older people.

Change in criteria for USP dissolution performance verification tests.

The US Pharmacopeial Convention has been evaluating its performance verification tests (PVT) for several years. These tests help ensure the integrity of the US Pharmacopeia performance test when a dissolution procedure, as described in General Chapter Dissolution <711>, is relied upon to test a nonsolution orally administered dosage form. One result of the evaluation is a change in the PVT criterion from one based on individual tablet results to one based on the mean and variability of a set of tablets. This paper describes the new PVT and its criterion and how its acceptance limits are derived from results of a collaborative study, explains a two-stage option for the test, and presents operating characteristics.

Drug Burden Index and Its Association With Hip Fracture Among Older Adults: A National Population-Based Study.

BACKGROUND: The Drug Burden Index (DBI) calculates the total sedative and anticholinergic load of prescribed medications and is associated with functional decline and hip fractures in older adults. However, it is unknown if confounding factors influence the relationship between the DBI and hip fractures. The objective of this study was to evaluate the association between the DBI and hip fractures, after correcting for mortality and multiple potential confounding factors. METHODS: A competing-risks regression analysis conducted on a prospectively recruited New Zealand community-dwelling older population who had a standardized (International Resident Assessment Instrument) assessment between September 1, 2012, and October 31, 2015, the study's end date. Outcome measures were survival status and hip fracture, with time-varying DBI exposure derived from 90-day time intervals. The multivariable competing-risks regression model was adjusted for a large number of medical comorbidities and activities of daily living. RESULTS: Among 70,553 adults assessed, 2,249 (3.2%) experienced at least one hip fracture, 20,194 (28.6%) died without experiencing a fracture, and 48,110 (68.2%) survived without a fracture. The mean follow-up time was 14.9 months (range: 1 day, 37.9 months). The overall DBI distribution was highly skewed, with median time-varying DBI exposure ranging from 0.93 (Q1 = 0.0, Q3 = 1.84) to 0.96 (Q1 = 0.0, Q3 = 1.90). DBI was significantly related to fracture incidence in unadjusted (p < .001) and adjusted (p < .001) analyses. The estimated subhazard ratio was 1.52 (95% confidence interval: 1.28-1.81) for those with DBI > 3 compared with those with DBI = 0 in the adjusted analysis. CONCLUSIONS: In this study, increasing DBI was associated with a higher likelihood of fractures after accounting for the competing risk of mortality and adjusting for confounders. The results of this unique study are important in validating the DBI as a guide for medication management and it could help reduce the risk of hip fractures in older adults.

Pharmacotherapy in Older Adults with Cardiovascular Disease: Report from an American College of Cardiology, American Geriatrics Society, and National Institute on Aging Workshop.

OBJECTIVES: To identify the top priority areas for research to optimize pharmacotherapy in older adults with cardiovascular disease (CVD). DESIGN: Consensus meeting. SETTING: Multidisciplinary workshop supported by the National Institute on Aging, the American College of Cardiology, and the American Geriatrics Society, February 6-7, 2017. PARTICIPANTS: Leaders in the Cardiology and Geriatrics communities, (officers in professional societies, journal editors, clinical trialists, Division chiefs), representatives from the NIA; National Heart, Lung, and Blood Institute; Food and Drug Administration; Centers for Medicare and Medicaid Services, Alliance for Academic Internal Medicine, Patient-Centered Outcomes Research Institute, Agency for Healthcare Research and Quality, pharmaceutical industry, and trainees and early career faculty with interests in geriatric cardiology. MEASUREMENTS: Summary of workshop proceedings and recommendations. RESULTS: To better align older adults' healthcare preferences with their care, research is needed to improve skills in patient engagement and communication. Similarly, to coordinate and meet the needs of older adults with multiple comorbidities encountering multiple healthcare providers and systems, systems and disciplines must be integrated. The lack of data from efficacy trials of CVD medications relevant to the majority of older adults creates uncertainty in determining the risks and benefits of many CVD therapies; thus, developing evidence-based guidelines for older adults with CVD is a top research priority. Polypharmacy and medication nonadherence lead to poor outcomes in older people, making research on appropriate prescribing and deprescribing to reduce polypharmacy and methods to improve adherence to beneficial therapies a priority. CONCLUSION: The needs and circumstances of older adults with CVD differ from those that the current medical system has been designed to meet. Optimizing pharmacotherapy in older adults will require new data from traditional and pragmatic research to determine optimal CVD therapy, reduce polypharmacy, increase adherence, and meet person-centered goals. Better integration of the multiple systems and disciplines involved in the care of older adults will be essential to implement and disseminate best practices. J Am Geriatr Soc 67:371-380, 2019.

Metrologic approaches to setting acceptance criteria: unacceptable and unusual characteristics.

Decisions regarding acceptance criteria in regulatory or compendial contexts are among the most difficult to make. Acceptance criteria aid in the identification, on the one hand, of materials with unacceptable characteristics that should not pass the tests and procedures or, on the other hand, of unusual characteristics that indicate materials that are unlikely to pass the tests and procedures. For relatively complex procedures metrological approaches can differentiate between intra- and inter-laboratory variation and clarify unacceptable and unusual data. Such testing requires collaborative studies in which each participating laboratory essentially compares itself to the other laboratories in the collaborative study. Laboratories that use the reference standard established by the collaborative study are conducting a performance verification test in which they compare their capabilities to those of laboratories in the collaborative study. This paper considers aspects of a series of complex issues involving unacceptable/unusual characteristics primarily in the context of USP's work but with implications for manufacturing science via considerations of process capability and Quality by Design and to measurement science. Ultimately, acceptance criteria support the availability of good quality, safe, and effective medicines for patients and consumers.

A drug burden index to define the functional burden of medications in older people.

BACKGROUND: Older people carry a high burden of illness for which medications are indicated, along with increased risk of adverse drug reactions. We developed an index to determine drug burden based on pharmacologic principles. We evaluated the relationship of this index to physical and cognitive performance apart from disease indication. METHODS: Data from the Health, Aging, and Body Composition Study on 3075 well-functioning community-dwelling persons aged 70 to 79 years were analyzed by multiple linear regression to assess the cross-sectional association of drug burden index with a validated composite continuous measure for physical function, and with the Digit Symbol Substitution Test for cognitive performance. RESULTS: Use of anticholinergic and sedative medications was associated with poorer physical performance score (anticholinergic exposure, 2.08 vs 2.21, P<.001; sedative exposure, 2.09 vs 2.19, P<.001) and cognitive performance on the Digit Symbol Substitution Test (anticholinergic exposure, 34.5 vs 35.5, P = .045; sedative exposure, 34.0 vs 35.5, P = .01). Associations were strengthened when exposure was calculated by principles of dose response. An increase of 1 U in drug burden index was associated with a deficit of 0.15 point (P<.001) on the physical function scale and 1.5 points (P = .01) on the Digit Symbol Substitution Test. These values were more than 3 times those associated with a single comorbid illness. CONCLUSIONS: The drug burden index demonstrates that anticholinergic and sedative drug exposure is associated with poorer function in community-dwelling older people. This pharmacologic approach provides a useful evidence-based tool for assessing the functional effect of exposure to medications in this population.

Drug Burden and its Association with Falls Among Older Adults in New Zealand: A National Population Cross-Sectional Study.

BACKGROUND: Adverse outcomes associated with advanced diseases are often exacerbated by polypharmacy. OBJECTIVES: The current study investigated an association between exposure to anticholinergic and sedative medicines and falls in community-dwelling older people, after controlling for potential confounders. METHODS: We conducted a retrospective cross-sectional study of a continuously recruited national cohort of community-dwelling New Zealanders aged 65 years and over. Participants had an International Resident Assessment Instrument-Home Care (interRAI-HC) assessment between 1 September 2012 and 31 January 2016. InterRAI-HC is a comprehensive, multi-domain, standardised assessment. This study captured 18 variables, including fall frequency, from the interRAI. These data were deterministically matched with the Drug Burden Index (DBI) for each participant, derived from an anonymised national dispensed pharmaceuticals database. DBI groupings were statistically ascertained, and ordinal regression models employed. RESULTS: Overall, there were 71,856 participants, with a mean age of 82.7 years (range 65-106); 43,802 (61.0%) were female, and 63,578 (88.5%) were New Zealand European. In unadjusted and adjusted analyses, DBI groupings were related to falls (p < 0.001). A DBI score > 3 was associated with a 41% increase in falls compared with a DBI score of 0 (p < 0.001). There was a 'dose-response' relationship between DBI levels and falls risk. CONCLUSIONS: DBI was found to be independently and positively associated with a greater risk of falls in this cohort after adjustment for 18 known confounders. We suggest that the DBI could be a valuable tool for clinicians to use alongside electronic prescribing to help reduce falls in older people.

Comparative molecular field analysis of the binding of the stereoisomers of fenoterol and fenoterol derivatives to the beta2 adrenergic receptor.

Stereoisomers of fenoterol and six fenoterol derivatives have been synthesized and their binding affinities for the beta2 adrenergic receptor (Kibeta2-AR), the subtype selectivity relative to the beta1-AR (Kibeta1-AR/Kibeta2-AR) and their functional activities were determined. Of the 26 compounds synthesized in the study, submicromolar binding affinities were observed for (R,R)-fenoterol, the (R,R)-isomer of the p-methoxy, and (R,R)- and (R,S)-isomers of 1-naphthyl derivatives and all of these compounds were active at submicromolar concentrations in cardiomyocyte contractility tests. The Kibeta1-AR/Kibeta2-AR ratios were >40 for (R,R)-fenoterol and the (R,R)-p-methoxy and (R,S)-1-naphthyl derivatives and 14 for the (R,R)-1-napthyl derivative. The binding data was analyzed using comparative molecular field analysis (CoMFA), and the resulting model indicated that the fenoterol derivatives interacted with two separate binding sites and one steric restricted site on the pseudo-receptor and that the chirality of the second stereogenic center affected Kibeta2 and subtype selectivity.

Caloric restriction reduces age-related pseudocapillarization of the hepatic sinusoid.

Age-related changes in the hepatic sinusoid, called pseudocapillarization, may contribute to the pathogenesis of dyslipidemia. Caloric restriction (CR) is a powerful model for the study of aging because it extends lifespan. We assessed the effects of CR on the hepatic sinusoid to determine whether pseudocapillarization is preventable and hence a target for the prevention of age-related dyslipidemia. Livers from young (6 months) and old (24 months) CR and ad libitum fed (AL) F344 rats were examined using electron microscopy and immunohistochemistry. In old age, there was increased thickness of the liver sinusoidal endothelium and reduced endothelial fenestration porosity. In old CR rats, endothelial thickness was less and fenestration porosity was greater than in old AL rats. Immunohistochemistry showed that CR prevented age-related decrease in caveolin-1 expression and increase in peri-sinusoidal collagen IV staining, but did not alter the age-related increase of von Willebrand's factor. CR reduces age-related pseudocapillarization of the hepatic sinusoid and correlates with changes in caveolin-1 expression.

Caloric restriction and intermittent fasting alter spectral measures of heart rate and blood pressure variability in rats.

Dietary restriction (DR) has been shown to increase life span, delay or prevent age-associated diseases, and improve functional and metabolic cardiovascular risk factors in rodents and other species. To investigate the effects of DR on beat-to-beat heart rate and diastolic blood pressure variability (HRV and DPV) in male Sprague-Dawley rats, we implanted telemetric transmitters and animals were maintained on either intermittent fasting (every other day feeding) or calorie-restricted (40% caloric reduction) diets. Using power spectral analysis, we evaluated the temporal profiles of the low- and high-frequency oscillatory components in heart rate and diastolic blood pressure signals to assess cardiac autonomic activity. Body weight, heart rate, and systolic and diastolic blood pressure were all found to decrease in response to DR. Both methods of DR produced decreases in the low-frequency component of DPV spectra, a marker for sympathetic tone, and the high-frequency component of HRV spectra, a marker for parasympathetic activity, was increased. These parameters required at least 1 month to become maximal, but returned toward baseline values rapidly once rats resumed ad libitum diets. These results suggest an additional cardiovascular benefit of DR that merits further studies of this potential effect in humans.

Use of Biomedical Ontologies for Integration of Biological Knowledge for Learning and Prediction of Adverse Drug Reactions.

Drug-induced toxicity is a major public health concern that leads to patient morbidity and mortality. To address this problem, the Food and Drug Administration is working on the PredicTox initiative, a pilot research program on tyrosine kinase inhibitors, to build mechanistic and predictive models for drug-induced toxicity. This program involves integrating data acquired during preclinical studies and clinical trials within pharmaceutical company development programs that they have agreed to put in the public domain and in publicly available biological, pharmacological, and chemical databases. The integration process is accommodated by biomedical ontologies, a set of standardized vocabularies that define terms and logical relationships between them in each vocabulary. We describe a few programs that have used ontologies to address biomedical questions. The PredicTox effort is leveraging the experience gathered from these early initiatives to develop an infrastructure that allows evaluation of the hypothesis that having a mechanistic understanding underlying adverse drug reactions will improve the capacity to understand drug-induced clinical adverse drug reactions.