Influence of spatial orientation training in a centrifuge on the ability of fighter pilots to assess the bank angle during flight without visual references.

Without visual references, non-pilots exposed to coordinated flight turns underestimate the bank angle, because of discordant information of the roll-angular displacement from the otoliths, consistently signaling vertical position, versus the semicircular canals, enabling detection of the displacement. Pilots may also use their ability to perceive the G load and knowledge of the relation between load and angle to assess the bank angle. Our aim was to investigate if the perception of bank angle can be improved by spatial-orientation training in a centrifuge. Sixteen pilots/pilot students assessed their roll tilt, in complete darkness, both during real coordinated flight turns and gondola centrifugation, at roll tilts of 30° and 60°. The experiments were repeated after a 3-wk period, during which 8 of the subjects performed 9 training sessions in the centrifuge, comprising feedback on roll angle vs G load, and on indicating requested angles. Before training, the subjects perceived in the aircraft and centrifuge respectively: 37(17)°; 38(14)° during 60° turns, and 19(12)°; 20(10)° during 30° turns. Training improved the perception of angle during the 60° [to 60(7)°; 55(10)°; p≤0.04], but not the 30° turns [21(10)°; 15(9)°; p≥0.30]; the improvement disappeared within two years after training. Angle assessments did not change in the untrained group. The results suggest that it is possible to, in a centrifuge, train a pilot's ability to perceive large, but not discrete-to-moderate roll-angular displacements. The transient training effect is attributable to improved capacity to perceive and translate G load into roll angle and/or to increased reliance on semicircular-canal signals.

Factors of significance for the ability of fighter pilots to visually indicate the magnitude of roll tilt during simulated turns in a centrifuge.

During coordinated flight and centrifugation, pilots show interindividual variability in perceived roll tilt. The study explored how this variability is related to perceptual and cognitive functions. Twelve pilots underwent three 6-min centrifugations on two occasions (G levels: 1.1G, 1.8G, and 2.5G; gondola tilts: 25°, 56°, and 66°). The subjective visual horizontal (SVH) was measured with an adjustable luminous line and the pilots gave estimates of experienced G level. Afterward, they were interrogated regarding the relationship between G level and roll tilt and adjusted the line to numerically mentioned angles. Generally, the roll tilt during centrifugation was underestimated, and there was a large interindividual variability. Both knowledge on the relationship between G level and bank angle, and ability to adjust the line according to given angles contributed to the prediction of SVH in a multiple regression model. However, in most cases, SVH was substantial smaller than predictions based on specific abilities.

Detection and Characterization of Walking Bouts Using a Single Wrist-Worn Accelerometer in Free-living Conditions.

Detection and characterization of abnormalities of movement are important to develop a method for detecting early signs of Parkinson's disease (PD). Most of the current research in detection of characteristic reduction of movements due to PD, known as parkinsonism, requires using a set of invasive sensors in a clinical or controlled environment. Actigraphy has been widely used in medical research as a non-invasive data acquisition method in free-living conditions for long periods of time. The proposed algorithm uses triaxial accelerometer data obtained through actigraphy to detect walking bouts at least 10 seconds long and characterize them using cadence and arm swing. Accurate detection of walking periods is the first step toward the characterization of movement based on gait abnormalities. The algorithm was based on a Walking Score (WS) derived using the value of the auto-correlation function (ACF) for the Resultant acceleration vector. The algorithm achieved a precision of 0.90, recall of 0.77, and F1 score of 0.83 compared to the expert scoring for walking bout detection. We additionally described a method to measure arm swing amplitude.

Visual measures of perceived roll tilt in pilots during coordinated flight and gondola centrifugation.

BACKGROUND: During a simulated coordinated turn in a gondola centrifuge, experienced pilots show a substantial inter-individual variability in visual measures of perceived roll tilt. Because of the centrifuge's small radius, the pattern of stimuli to the semicircular canals during acceleration of the centrifuge differs in certain respects from that of an aircraft entering a turn. OBJECTIVE: To explore whether these differences may be of significance for the pilot's roll- plane orientation and whether individual characteristics revealed in the centrifuge correspond to those during real flight. METHOD: 8 fixed-wing air-force pilots were tested in a centrifuge and a high-performance aircraft. The centrifuge was accelerated to 2 G (gondola inclination 60°) within 10 s. The duration at 2 G was 6 minutes. Similar profiles were created in the aircraft. The subjective visual horizontal (SVH) was measured using an adjustable luminous line in darkness. Each pilot was tested on three occasions: centrifuge (2 runs), aircraft (2 turns), centrifuge (2 runs). For each 2-G exposure, initial and final SVH values were established via curve fitting. RESULT: Despite a large inter-individual variability (±SD), group means were similar in the aircraft (initial: 43.0±20.6°; final: 22.5±14.8°) and centrifuge (initial: 40.6±17.0°; final: 20.5±16.0°). Further, individual peculiarities in response patterns were similar in the two conditions. For both the initial and final SVH tilt there was a high correlation between centrifuge and aircraft. CONCLUSION: The correspondence between conditions suggests that the centrifuge is an adequate means for demonstrating the fundamental motion pattern of coordinated flight and also for establishing the individual pilot's ability to perceive an aircraft's roll attitude.Findings are discussed in connection with vestibular learning and the possibility of underlying differences between pilots in the keenness for semicircular canal and somatosensory cues.

Investigating discovery strategies and pharmacological properties of stereodefined phosphorodithioate LNA gapmers.

The introduction of sulfur into the phosphate linkage of chemically synthesized oligonucleotides creates the stereocenters on phosphorus atoms. Researchers have valued the nature of backbone stereochemistry and early on investigated drug properties for the individual stereocenters in dimers or short oligomers. Only very recently, it has become possible to synthesize fully stereodefined antisense oligonucleotides in good yield and purity. Non-bridging phosphorodithioate (PS2) introduces second sulfur into the phosphorothioate linkage to remove the chirality of phosphorus atom. Here, we describe the application of symmetrical non-bridging PS2 linkages in the context of stereodefined locked nucleic acids (LNAs) antisense oligonucleotides with the goal of reducing chiral complexity and, ultimately, resulting in single molecules. In addition, we propose a rather simple strategy to rapidly identify stereodefined gapmers, combining PS2 and a preferred stereochemistry motif (RSSR), which supports RNase-H-mediated target knockdown. Pharmacological efficacy and metabolic stability are investigated systematically using ApoB as a target sequence, where in vivo data correlate well to what is observed in vitro.

Correction: A Model for Estimating Biological Age From Physiological Biomarkers of Healthy Aging: Cross-sectional Study.

[This corrects the article DOI: 10.2196/35696.].

A Model for Estimating Biological Age From Physiological Biomarkers of Healthy Aging: Cross-sectional Study.

BACKGROUND: Individual differences in the rate of aging and susceptibility to disease are not accounted for by chronological age alone. These individual differences are better explained by biological age, which may be estimated by biomarker prediction models. In the light of the aging demographics of the global population and the increase in lifestyle-related morbidities, it is interesting to invent a new biological age model to be used for health promotion. OBJECTIVE: This study aims to develop a model that estimates biological age based on physiological biomarkers of healthy aging. METHODS: Carefully selected physiological variables from a healthy study population of 100 women and men were used as biomarkers to establish an estimate of biological age. Principal component analysis was applied to the biomarkers and the first principal component was used to define the algorithm estimating biological age. RESULTS: The first principal component accounted for 31% in women and 25% in men of the total variance in the biological age model combining mean arterial pressure, glycated hemoglobin, waist circumference, forced expiratory volume in 1 second, maximal oxygen consumption, adiponectin, high-density lipoprotein, total cholesterol, and soluble urokinase-type plasminogen activator receptor. The correlation between the corrected biological age and chronological age was r=0.86 (P<.001) and r=0.81 (P<.001) for women and men, respectively, and the agreement was high and unbiased. No difference was found between mean chronological age and mean biological age, and the slope of the regression line was near 1 for both sexes. CONCLUSIONS: Estimating biological age from these 9 biomarkers of aging can be used to assess general health compared with the healthy aging trajectory. This may be useful to evaluate health interventions and as an aid to enhance awareness of individual health risks and behavior when deviating from this trajectory. TRIAL REGISTRATION: ClinicalTrials.gov NCT03680768; https://clinicaltrials.gov/ct2/show/NCT03680768. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.2196/19209.

Addressing Today's Absorption, Distribution, Metabolism, and Excretion (ADME) Challenges in the Translation of In Vitro ADME Characteristics to Humans: A Case Study of the SMN2 mRNA Splicing Modifier Risdiplam.

Small molecules that present complex absorption, distribution, metabolism, and elimination (ADME) properties can be challenging to investigate as potential therapeutics. Acquiring data through standard methods can yield results that are insufficient to describe the in vivo situation, which can affect downstream development decisions. Implementing in vitro-in vivo-in silico strategies throughout the drug development process is effective in identifying and mitigating risks while speeding up their development. Risdiplam (Evrysdi)-an orally bioavailable, small molecule approved by the US Food and Drug Administration and more recently by the European Medicines Agency for the treatment of patients ≥2 months of age with spinal muscular atrophy-is presented here as a case study. Risdiplam is a low-turnover compound whose metabolism is mediated through a non-cytochrome P450 enzymatic pathway. Four main challenges of risdiplam are discussed: predicting in vivo hepatic clearance, determining in vitro metabolites with regard to metabolites in safety testing guidelines, elucidating enzymes responsible for clearance, and estimating potential drug-drug interactions. A combination of in vitro and in vivo results was successfully extrapolated and used to develop a robust physiologically based pharmacokinetic model of risdiplam. These results were verified through early clinical studies, further strengthening the understanding of the ADME properties of risdiplam in humans. These approaches can be applied to other compounds with similar ADME profiles, which may be difficult to investigate using standard methods. SIGNIFICANCE STATEMENT: Risdiplam is the first approved, small-molecule, survival of motor neuron 2 mRNA splicing modifier for the treatment of spinal muscular atrophy. The approach taken to characterize the absorption, distribution, metabolism, and excretion (ADME) properties of risdiplam during clinical development incorporated in vitro-in vivo-in silico techniques, which may be applicable to other small molecules with challenging ADME. These strategies may be useful in improving the speed at which future drug molecules can be developed.

In vitro and clinical investigations to determine the drug-drug interaction potential of entrectinib, a small molecule inhibitor of neurotrophic tyrosine receptor kinase (NTRK).

Background Entrectinib is a CNS-active, potent inhibitor of tyrosine receptor kinases A/B/C, ROS1 and anaplastic lymphoma kinase approved for use in patients with solid tumors. We describe the in vitro and clinical studies investigating potential entrectinib drug-drug interactions. Methods In vitro studies with human biomaterials assessed the enzymes involved in entrectinib metabolism, and whether entrectinib modulates the activity of the major cytochrome P450 (CYP) enzymes or drug transporter P-glycoprotein. Clinical studies investigated the effect of a strong CYP3A4 inhibitor (itraconazole) and inducer (rifampin) on single-dose entrectinib pharmacokinetics. The effect of entrectinib on sensitive probe substrates for CYP3A4 (midazolam) and P-glycoprotein (digoxin) were also investigated. Results Entrectinib is primarily metabolized by CYP3A4. In vitro, entrectinib is a CYP3A4/5 inhibitor (IC50 2 µM) and a weak CYP3A4 inducer. Entrectinib inhibited P-glycoprotein (IC50 1.33 µM) but is a poor substrate. In healthy subjects, itraconazole increased entrectinib Cmax and AUC by 73% and 504%, respectively, and rifampin decreased entrectinib Cmax and AUC by 56% and 77%, respectively. Single dose entrectinib did not affect midazolam AUC, although Cmax decreased by 34%. Multiple dose entrectinib increased midazolam AUC by 50% and decreased Cmax by 21%. Single dose entrectinib increased digoxin AUC and Cmax by 18% and 28%, respectively, but did not affect digoxin renal clearance. Conclusions Entrectinib is a CYP3A4 substrate and is sensitive to the effects of coadministered moderate/strong CYP3A4 inhibitors and strong inducers, and requires dose adjustment. Entrectinib is a weak inhibitor of CYP3A4 and P-glycoprotein and no dose adjustments are required with CYP3A4/P- glycoprotein substrates.Registration Number (Study 2) NCT03330990 (first posted online November 6, 2017) As studies 1 and 3 are phase 1 trials in healthy subjects, they are not required to be registered.

Detecting cocoa plantations in Côte d'Ivoire and Ghana and their implications on protected areas.

Côte d'Ivoire and Ghana are the largest producers of cocoa in the world. In recent decades the cultivation of this crop has led to the loss of vast tracts of forest areas in both countries. Efficient and accurate methods for remotely identifying cocoa plantations are essential to the implementation of sustainable cocoa practices and for the periodic and effective monitoring of forests. In this study, a method for cocoa plantation identification was developed based on a multi-temporal stack of Sentinel-1 and Sentinel-2 images and a multi-feature Random Forest (RF) algorithm. The Normalized Difference Vegetation Index (NDVI) and second-order texture features were assessed for their importance in an RF classification, and their optimal combination was used as input variables for the RF model to identify cocoa plantations in both countries. The RF model-based cocoa map achieved 82.89% producer's and 62.22% user's accuracy, detecting 3.69 million hectares (Mha) and 2.15 Mha of cocoa plantations for Côte d'Ivoire and Ghana, respectively. The results demonstrate that a combination of an RF model and multi-feature classification can distinguish cocoa plantations from other land cover/use, effectively reducing feature dimensions and improving classification efficiency. The results also highlight that cocoa farms largely encroach into protected areas (PAs), as 20% of the detected cocoa plantation area is located in PAs and almost 70% of the PAs in the study area house cocoa plantations.

Arousal characteristics in patients with Parkinson's disease and isolated rapid eye movement sleep behavior disorder.

STUDY OBJECTIVES: Patients diagnosed with isolated rapid eye movement (REM) sleep behavior disorder (iRBD) and Parkinson's disease (PD) have altered sleep stability reflecting neurodegeneration in brainstem structures. We hypothesize that neurodegeneration alters the expression of cortical arousals in sleep. METHODS: We analyzed polysomnography data recorded from 88 healthy controls (HC), 22 iRBD patients, 82 de novo PD patients without RBD, and 32 with RBD (PD + RBD). These patients were also investigated at a 2-year follow-up. Arousals were analyzed using a previously validated automatic system, which used a central electroencephalography lead, electrooculography, and chin electromyography. Multiple linear regression models were fitted to compare group differences at baseline and change to follow-up for arousal index (ArI), shifts in electroencephalographic signals associated with arousals, and arousal chin muscle tone. The regression models were adjusted for known covariates affecting the nature of arousal. RESULTS: In comparison to HC, patients with iRBD and PD + RBD showed increased ArI during REM sleep and their arousals showed a significantly lower shift in α-band power at arousals and a higher muscle tone during arousals. In comparison to HC, the PD patients were characterized by a decreased ArI in non-REM (NREM) sleep at baseline. ArI during NREM sleep decreased further at the 2-year follow-up, although not significantly. CONCLUSIONS: Patients with PD and iRBD present with abnormal arousal characteristics as scored by an automated method. These abnormalities are likely to be caused by neurodegeneration of the reticular activation system due to alpha-synuclein aggregation.

Safety, Tissue Distribution, and Metabolism of LNA-Containing Antisense Oligonucleotides in Rats.

Antisense oligonucleotides (ASOs) are chemically modified nucleic acids with therapeutic potential, some of which have been approved for marketing. We performed a study in rats to investigate mechanisms of toxicity after administration of 3 tool locked nucleic acid (LNA)-containing ASOs with differing established safety profiles. Four male rats per group were dosed once, 3, or 6 times subcutaneously, with 7 days between dosing, and sacrificed 3 days after the last dose. These ASOs were either unconjugated (naked) or conjugated with N-acetylgalactosamine for hepatocyte-targeted delivery. The main readouts were in-life monitoring, clinical and anatomic pathology, exposure assessment and metabolite identification in liver and kidney by liquid chromatography coupled to tandem mass spectrometry, ASO detection in liver and kidney by immunohistochemistry, in situ hybridization, immune electron microscopy, and matrix-assisted laser desorption/ionization mass spectrometry imaging. The highly toxic compounds showed the greatest amount of metabolites and a low degree of tissue accumulation. This study reveals different patterns of cell death associated with toxicity in liver (apoptosis and necrosis) and kidney (necrosis only) and provides new ultrastructural insights on the tissue accumulation of ASOs. We observed that the immunostimulatory properties of ASOs can be either primary from sequence-dependent properties or secondary to cell necrosis.

Multiorgan Crystal Deposition of an Amphoteric Drug in Rats Due to Lysosomal Accumulation and Conversion to a Poorly Soluble Hydrochloride Salt.

Poor solubility of drug candidates mainly affects bioavailability, but poor solubility of drugs and metabolites can also lead to precipitation within tissues, particularly when high doses are tested. RO0728617 is an amphoteric compound bearing basic and acidic moieties that has previously demonstrated good solubility at physiological pH but underwent widespread crystal deposition in multiple tissues in rat toxicity studies. The aim of our investigation was to better characterize these findings and their underlying mechanism(s), and to identify possible screening methods in the drug development process. Main microscopic features observed in rat RO0728617 toxicity studies were extensive infiltrates of crystal-containing macrophages in multiple organs. Matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry revealed that these crystals contained the orally administered parent compound, and locality was confirmed to be intracytoplasmic and partly intralysosomal by electron microscopic examination. Crystal formation was explained by lysosomal accumulation of the compound followed by precipitation of the hydrochloride salt under physiological conditions in the lysosomes, which have a lower pH and higher chloride concentration in comparison to the cytosol. This study demonstrates that risk of drug precipitation can be assessed by comparing the estimated lysosomal drug concentration at a given dose with the solubility of the compound at lysosomal conditions.

Characterization of the pharmacokinetics of entrectinib and its active M5 metabolite in healthy volunteers and patients with solid tumors.

BACKGROUND: Entrectinib is an oral, CNS-active, potent inhibitor of tyrosine receptor kinases A/B/C, tyrosine kinase ROS proto-oncogene 1, and anaplastic lymphoma kinase approved for use in patients with solid tumors. We describe 3 clinical studies, including one investigating the single/multiple dose pharmacokinetics of entrectinib in patients and two studies in healthy volunteers investigating the absorption/distribution/metabolism/excretion (ADME) of entrectinib, its relative bioavailability, and effect of food on pharmacokinetics. METHODS: The patient study is open-label with dose-escalation and expansion phases. Volunteers received entrectinib (100-400 mg/m2, and 600-800 mg) once daily with food in continuous 28-day cycles. In the ADME study, volunteers received a single oral dose of [14C]entrectinib 600 mg. In the third study, volunteers received single doses of entrectinib 600 mg as the research and marketed formulations in the fasted state (Part 1), and the marketed formulation in the fed and fasted states (Part 2). Entrectinib and its major active metabolite M5 were assessed in all studies. RESULTS: Entrectinib was absorbed in a dose-dependent manner with maximum concentrations at ~4 h postdose and an elimination half-life of ~20 h. Entrectinib was cleared mainly through metabolism and both entrectinib and metabolites were eliminated mainly in feces (minimal renal excretion). At steady-state, the M5-to-entrectinib AUC ratio was 0.5 (with 600 mg entrectinib research formulation in patients). The research and marketed formulations were bioequivalent and food had no relevant effect on pharmacokinetics. CONCLUSIONS: Entrectinib is well absorbed, with linear PK that is suitable for once-daily dosing, and can be taken with or without food.

A Biological Age Model Designed for Health Promotion Interventions: Protocol for an Interdisciplinary Study for Model Development.

BACKGROUND: Actions to improve healthy aging and delay morbidity are crucial, given the global aging population. We believe that biological age estimation can help promote the health of the general population. Biological age reflects the heterogeneity in functional status and vulnerability to disease that chronological age cannot. Thus, biological age assessment is a tool that provides an intuitively meaningful outcome for the general population, and as such, facilitates our understanding of the extent to which lifestyle can increase health span. OBJECTIVE: This interdisciplinary study intends to develop a biological age model and explore its usefulness. METHODS: The model development comprised three consecutive phases: (1) conducting a cross-sectional study to gather candidate biomarkers from 100 individuals representing normal healthy aging people (the derivation cohort); (2) estimating the biological age using principal component analysis; and (3) testing the clinical use of the model in a validation cohort of overweight adults attending a lifestyle intervention course. RESULTS: We completed the data collection and analysis of the cross-sectional study, and the initial results of the principal component analysis are ready. Interpretation and refinement of the model is ongoing. Recruitment to the validation cohort is forthcoming. We expect the results to be published by December 2021. CONCLUSIONS: We expect the biological age model to be a useful indicator of disease risk and metabolic risk, and further research should focus on validating the model on a larger scale. TRIAL REGISTRATION: ClinicalTrials.gov NCT03680768, https://clinicaltrials.gov/ct2/show/NCT03680768 (Phase 1 study); NCT04279366 https://clinicaltrials.gov/ct2/show/NCT04279366 (Phase 3 study). INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/19209.

Only Hyperuricemia with Crystalluria, but not Asymptomatic Hyperuricemia, Drives Progression of Chronic Kidney Disease.

BACKGROUND: The roles of asymptomatic hyperuricemia or uric acid (UA) crystals in CKD progression are unknown. Hypotheses to explain links between UA deposition and progression of CKD include that (1) asymptomatic hyperuricemia does not promote CKD progression unless UA crystallizes in the kidney; (2) UA crystal granulomas may form due to pre-existing CKD; and (3) proinflammatory granuloma-related M1-like macrophages may drive UA crystal-induced CKD progression. METHODS: MALDI-FTICR mass spectrometry, immunohistochemistry, 3D confocal microscopy, and flow cytometry were used to characterize a novel mouse model of hyperuricemia and chronic UA crystal nephropathy with granulomatous nephritis. Interventional studies probed the role of crystal-induced inflammation and macrophages in the pathology of progressive CKD. RESULTS: Asymptomatic hyperuricemia alone did not cause CKD or drive the progression of aristolochic acid I-induced CKD. Only hyperuricemia with UA crystalluria due to urinary acidification caused tubular obstruction, inflammation, and interstitial fibrosis. UA crystal granulomas surrounded by proinflammatory M1-like macrophages developed late in this process of chronic UA crystal nephropathy and contributed to the progression of pre-existing CKD. Suppressing M1-like macrophages with adenosine attenuated granulomatous nephritis and the progressive decline in GFR. In contrast, inhibiting the JAK/STAT inflammatory pathway with tofacitinib was not renoprotective. CONCLUSIONS: Asymptomatic hyperuricemia does not affect CKD progression unless UA crystallizes in the kidney. UA crystal granulomas develop late in chronic UA crystal nephropathy and contribute to CKD progression because UA crystals trigger M1-like macrophage-related interstitial inflammation and fibrosis. Targeting proinflammatory macrophages, but not JAK/STAT signaling, can attenuate granulomatous interstitial nephritis.

Identification and Preclinical Development of a 2,5,6-Trisubstituted Fluorinated Pyridine Derivative as a Radioligand for the Positron Emission Tomography Imaging of Cannabinoid Type 2 Receptors.

Despite the broad implications of the cannabinoid type 2 receptor (CB2) in neuroinflammatory processes, a suitable CB2-targeted probe is currently lacking in clinical routine. In this work, we synthesized 15 fluorinated pyridine derivatives and tested their binding affinities toward CB2 and CB1. With a sub-nanomolar affinity (Ki for CB2) of 0.8 nM and a remarkable selectivity factor of >12,000 over CB1, RoSMA-18-d6 exhibited outstanding in vitro performance characteristics and was radiofluorinated with an average radiochemical yield of 10.6 ± 3.8% (n = 16) and molar activities ranging from 52 to 65 GBq/µmol (radiochemical purity > 99%). [18F]RoSMA-18-d6 showed exceptional CB2 attributes as demonstrated by in vitro autoradiography, ex vivo biodistribution, and positron emission tomography (PET). Further, [18F]RoSMA-18-d6 was used to detect CB2 upregulation on postmortem human ALS spinal cord tissues. Overall, these results suggest that [18F]RoSMA-18-d6 is a promising CB2 PET radioligand for clinical translation.

Design of a deep learning model for automatic scoring of periodic and non-periodic leg movements during sleep validated against multiple human experts.

OBJECTIVE: Currently, manual scoring is the gold standard of leg movement scoring (LMs) and periodic LMs (PLMS) in overnight polysomnography (PSG) studies, which is subject to inter-scorer variability. The objective of this study is to design and validate an end-to-end deep learning system for the automatic scoring of LMs and PLMS in sleep. METHODS: The deep learning system was developed, validated and tested, with respect to manual annotations by expert technicians on 800 overnight PSGs using a leg electromyography channel. The study includes data from three cohorts, namely, the Wisconsin Sleep Cohort (WSC), Stanford Sleep Cohort (SSC) and MrOS Sleep Study. The performance of the system was further compared against individual expert technicians and existing PLM detectors. RESULTS: The system achieved an F1 score of 0.83, 0.71, and 0.77 for the WSC, SSC, and an ancillary study (Osteoporotic Fractures in Men Study, MrOS) cohorts, respectively. In a total of 60 PSGs from the WSC and the SSC scored by nine expert technicians, the system performed better than two and comparable to seven of the individual scorers with respect to a majority-voting consensus of the remaining scorers. In 60 PSGs from the WSC scored accurately for PLMS, the system outperformed four previous PLM detectors, which were all evaluated on the same data, with an F1 score of 0.85. CONCLUSIONS: The proposed system performs better or comparable to individual expert technicians while outperforming previous automatic detectors. Thereby, the study validates fully automatic methods for scoring LMs in sleep.

Genotoxicity Assessment of Drug Metabolites in the Context of MIST and Beyond.

While there are dedicated guidelines for industry regarding the assessment of the genotoxic potential of new pharmaceuticals and impurities, and the general safety assessment of major drug metabolites, only limited guidance exists on the assessment of potential genotoxic minor drug metabolites. In this Perspective, we discuss challenges associated with assessing the genotoxic potential of human metabolites and share five case studies within the context of an "aware-avoid-assess" paradigm. A special focus is on a class of potentially genotoxic carcinogens, aromatic amines (arylamines and anilines). This compound class is frequently used as building blocks and may show up as impurities, metabolites, or degradants in pharmaceuticals. We propose several recommendations that should help project teams at different stages of pharmaceutical development. In most cases, proactive interactions with the relevant health authority should be considered to endorse the proposed genotoxicity assessment strategy for minor drug metabolites.

Qualification of impurities based on metabolite data.

Regulatory Guidance documents ICH Q3A (R2) and ICH Q3B (R2) state that "impurities that are also significant metabolites present in animal and/or human studies are generally considered qualified". However, no guidance is provided regarding data requirements for qualification, nor is a definition of the term "significant metabolite" provided. An opportunity is provided to define those categories and potentially avoid separate toxicity studies to qualify impurities. This can reduce cost, animal use and time, and avoid delays in drug development progression. If the concentration or amount of a metabolite, in animals or human, is similar to that of the known, structurally identical impurity (arising from the administered test material), the qualification of the impurity on the grounds of it also being a metabolite is justified. We propose two complementary approaches to support conclusions to this effect: 1) demonstrate that the impurity is formed by metabolism in animals and/or man, based preferably on plasma exposures or, alternatively, amounts excreted in urine, and, where appropriate, 2) show that animal exposure to (or amount of) the impurity/metabolite is equal or greater in animals than in humans. An important factor of both assessments is the maximum theoretical concentration (or amount) (MTC or MTA) of the impurity/metabolite achievable from the administered dose and recommendations on the estimation of the MTC and MTA are presented.