ABSTRACT
Individual sensitivity to environmental exposures may be genetically influenced. This genotype-by-environment interplay implies differences in phenotypic variance across genotypes. However, environmental sensitivity genetic variants have proven challenging to detect. GWAS of monozygotic twin differences is a family-based variance analysis method, which is more robust to systemic biases that impact population-based methods. We combined data from up to 21,792 monozygotic twins (10,896 pairs) from 11 studies to conduct the largest GWAS meta-analysis of monozygotic phenotypic differences in children and adolescents/adults for seven psychiatric and neurodevelopmental phenotypes: attention deficit hyperactivity disorder (ADHD) symptoms, autistic traits, anxiety and depression symptoms, psychotic-like experiences, neuroticism, and wellbeing. The SNP-heritability of variance in these phenotypes were estimated (h2: 0% to 18%), but were imprecise. We identified a total of 13 genome-wide significant associations (SNP, gene, and gene-set), including genes related to stress-reactivity for depression, growth factor-related genes for autistic traits and catecholamine uptake-related genes for psychotic-like experiences. Monozygotic twins are an important new source of evidence about the genetics of environmental sensitivity.
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The use of genetic testing has enhanced the diagnostic accuracy of heritable genetic cardiomyopathies. However, it remains unclear how genetic information is interpreted and incorporated into clinical practice for children with cardiomyopathy. The primary aim of this study was to understand how clinical practice differs regarding sequence variant classifications amongst pediatric cardiologists who treat children with cardiomyopathy. A secondary aim was to understand the availability of genetic testing and counseling resources across participating pediatric cardiomyopathy programs. An electronic survey was distributed to pediatric heart failure, cardiomyopathy, or heart transplantation physicians between August and September 2022. A total of 106 individual providers from 68 unique centers responded to the survey. Resources for genetic testing and genetic counseling vary among large pediatric cardiomyopathy programs. A minority of centers reported having a geneticist (N = 16, 23.5%) or a genetic counselor (N = 21, 31%) on faculty within the division of pediatric cardiology. A total of 9 centers reported having both (13%). Few centers (N = 13, 19%) have a formal process in place to re-engage patients who were previously discharged from cardiology follow-up if variant reclassification would alter clinical management. Clinical practice patterns were uniform in response to pathogenic or likely pathogenic variants but were more variable for variants of uncertain significance. Efforts to better incorporate genetic expertise and resources into the clinical practice of pediatric cardiomyopathy may help to standardize the interpretation of genetic information and better inform clinical decision-making surrounding heritable cardiomyopathies.
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BACKGROUND: Functional motor disorder-the motor variant of functional neurological disorder-is a disabling condition that is commonly associated with poor health outcomes. Pathophysiological models have inspired new treatment approaches such as specialist physiotherapy, although evidence from large randomised controlled trials is absent. We aimed to assess the clinical effectiveness of a specialist physiotherapy intervention for functional motor disorder compared with treatment as usual. METHODS: In this pragmatic, multicentre, phase 3 randomised controlled trial at 11 hospitals in England and Scotland, adults with a clinically definite diagnosis of functional motor disorder, diagnosed by a neurologist, were included. Participants were randomly assigned (1:1, stratified by site) using a remote web-based application to either specialist physiotherapy (a protocolised intervention of nine sessions plus follow-up) or treatment as usual (referral to local community neurological physiotherapy). Individuals working on data collection and analysis were masked to treatment allocation. The primary outcome was the physical functioning domain of the 36-item short form health questionnaire (SF36) at 12 months after randomisation. The primary analysis followed a modified intention-to-treat principle, using a complete case approach; participants who were unable to receive their randomised treatment due to the suspension of health-care services during the COVID-19 pandemic were excluded from the primary analysis. This trial is registered with the International Standard Randomised Controlled Trial registry, ISRCTN56136713, and is completed. FINDINGS: Recruitment occurred between Oct 19, 2018, and March 11, 2020, pausing during the COVID-19 lockdown, and resuming from Aug 3, 2021, to Jan 31, 2022. Of 355 participants who were enrolled, 179 were randomly assigned to specialist physiotherapy and 176 to treatment as usual. 89 participants were excluded from the primary analysis due to COVID-19 interruption to treatment (27 were assigned to specialist physiotherapy and 62 to treatment as usual). After accounting for withdrawals (n=11) and loss to follow-up (n=14), the primary analysis included data from 241 participants (138 [91%] assigned specialist physiotherapy and 103 [90%] assigned treatment as usual). Physical functioning, as assessed by SF36, did not differ significantly between groups (adjusted mean difference 3·5, 95% CI -2·3 to 9·3; p=0·23). There were no serious adverse events related to the trial interventions. 35 serious adverse events were recorded in the specialist physiotherapy group by 24 participants (17·0%), and 24 serious adverse events were recorded in the treatment as usual group by 18 participants (17·0%); one death occurred in the specialist physiotherapy group (cause of death was recorded as suicide). All were considered unrelated to specialist physiotherapy. INTERPRETATION: Although more participants who were assigned specialist physiotherapy self-rated their motor symptoms as improved and had better scores on subjective measures of mental health, the intervention did not result in better self-reported physical functioning at 12 months. Both the specialist and community neurological physiotherapy appeared to be a safe and a valued treatment for selected patients with functional motor disorder. Future research should continue to refine interventions for people with functional motor disorder and develop evidence-based methods to guide treatment triage decisions. FUNDING: National Institute for Health and Care Research and Health Technology Assessment Programme.
Subject(s)
COVID-19 , Physical Therapy Modalities , Humans , Male , Female , Scotland , Middle Aged , England , Adult , COVID-19/epidemiology , Aged , Treatment Outcome , SARS-CoV-2ABSTRACT
INTRODUCTION: This process evaluation was conducted in parallel to the randomised controlled feasibility trial of NIDUS-Professional, a manualised remote dementia training intervention for homecare workers (HCWs), delivered alongside an individualised intervention for clients living with dementia and their family carers (NIDUS-Family). The process evaluation reports on: (i) intervention reach, dose and fidelity; (ii) contexts influencing agency engagement and (iii) alignment of findings with theoretical assumptions about how the intervention might produce change. METHODS: We report proportions of eligible HCWs receiving any intervention (reach), number of sessions attended (dose; attending ≥4/6 main sessions was predefined as adhering), intervention fidelity and adherence of clients and carers to NIDUS-Family (attending all 6-8 planned sessions). We interviewed HCWs, managers, family carers and facilitators. We integrated and thematically analysed, at the homecare agency level, qualitative interview and intervention recording data. RESULTS: 32/141 (23%) of eligible HCWs and 7/42 (17%) of family carers received any intervention; most who did adhered to the intervention (89% and 71%). Intervention fidelity was high. We analysed interviews with 20/44 HCWs, 3/4 managers and 3/7 family carers, as well as intervention recordings involving 32/44 HCWs. All agencies reported structural challenges in supporting intervention delivery. Agencies with greater management buy-in had higher dose and reach. HCWs valued NIDUS-Professional for enabling group reflection and peer support, providing practical, actionable care strategies and increasing their confidence as practitioners. CONCLUSION: NIDUS-Professional was valued by HCWs. Agency management, culture and priorities were key barriers to implementation; we discuss how to address these in a future trial.
Subject(s)
Caregivers , Dementia , Home Care Services , Home Health Aides , Humans , Dementia/therapy , Dementia/psychology , Caregivers/education , Home Health Aides/education , Home Health Aides/psychology , Male , Female , Health Knowledge, Attitudes, Practice , United Kingdom , Process Assessment, Health Care , Middle Aged , Attitude of Health Personnel , Interviews as TopicABSTRACT
Myxoid leiomyosarcoma (MLS) is a rare but well-documented tumor that often portends a poor prognosis compared to the conventional leiomyosarcoma. This rare sarcoma has been reported in the uterus, external female genitalia, soft tissue, and other locations. However, a definite rectal MLS has not been reported. Recently five cases of MLS were reported to harbor PLAG1 fusions (TRPS1::PLAG1, RAD51B::PLAG1, and TRIM13::PLAG1). In this report, we present a case of rectal MLS with a novel MIR143HG::PLAG1 fusion detected by RNA next-generation sequencing.
Subject(s)
DNA-Binding Proteins , Leiomyosarcoma , Rectal Neoplasms , Humans , Leiomyosarcoma/genetics , Leiomyosarcoma/pathology , Rectal Neoplasms/genetics , Rectal Neoplasms/pathology , DNA-Binding Proteins/genetics , Female , MicroRNAs/genetics , Middle Aged , Oncogene Proteins, Fusion/geneticsABSTRACT
INTRODUCTION: In the first randomised controlled trial of a dementia training and support intervention in UK homecare agencies, we aimed to assess: acceptability of our co-designed, manualised training, delivered by non-clinical facilitators; outcome completion feasibility; and costs for a future trial. METHODS: This cluster-randomised (2:1) single-blind, feasibility trial involved English homecare agencies. Intervention arm agency staff were offered group videocall sessions: 6 over 3 months, then monthly for 3 months (NIDUS-professional). Family carers (henceforth carers) and clients with dementia (dyads) were offered six to eight complementary, individual intervention sessions (NIDUS-Family). We collected potential trial measures as secondary outcomes remotely at baseline and 6 months: HCW (homecare worker) Work-related Strain Inventory (WRSI), Sense of Competence (SoC); proxy-rated Quality of Life (QOL), Disability Assessment for Dementia scale (DAD), Neuropsychiatric Inventory (NPI) and Homecare Satisfaction (HCS). RESULTS: From December 2021 to September 2022, we met agency (4 intervention, 2 control) and HCWs (n = 62) recruitment targets and recruited 16 carers and 16/60 planned clients. We met a priori progression criteria for adherence (≥4/6 sessions: 29/44 [65.9%,95% confidence interval (CI): 50.1,79.5]), HCW or carer proxy-outcome completion (15/16 (93.8% [69.8,99.8]) and proceeding with adaptation for HCWs outcome completion (46/63 (73.0% [CI: 60.3,83.4]). Delivery of NIDUS-Professional costs was £6,423 (£137 per eligible client). WRSI scores decreased and SoC increased at follow-up, with no significant between-group differences. For intervention arm proxy-rated outcomes, carer-rated QOL increased, HCW-rated was unchanged; carer and HCW-rated NPI decreased; DAD decreased (greater disability) and HCS was unchanged. CONCLUSION: A pragmatic trial is warranted; we will consider using aggregated, agency-level client outcomes, including neuropsychiatric symptoms.
Subject(s)
Dementia , Quality of Life , Humans , Dementia/diagnosis , Dementia/therapy , Feasibility Studies , Single-Blind Method , Caregivers/psychologyABSTRACT
We previously discovered that electron attachment to gaseous peptide anions can occur within a relatively narrow electron energy range. The resulting charge-increased radical ions undergo dissociation analogous to conventional cation electron capture/transfer dissociation (ECD/ETD), thus enabling a novel tandem mass spectrometry (MS/MS) technique that we termed negative ion electron capture dissociation (niECD). We proposed that gaseous zwitterionic structures are required for niECD with electron capture either occurring at or being directed by a positively charged site. Here, we further evaluate this zwitterion mechanism by performing niECD of peptides derivatized to alter their ability to form zwitterionic gaseous structures. Introduction of a fixed positive charge tag, a highly basic guanidino group, or a highly acidic sulfonate group to promote zwitterionic structures in singly charged anions, rescued the niECD ability of a peptide refractory to niECD in its unmodified form. We also performed a systematic study of five sets of synthetic peptides with decreasing zwitterion propensity and found that niECD efficiency decreased accordingly, further supporting the zwitterion mechanism. However, traveling-wave ion mobility-mass spectrometry experiments, performed to gain further insight into the gas-phase structures of peptides showing high niECD efficiency, exhibited an inverse correlation between the orientationally averaged collision cross sections and niECD efficiency. These results indicate that compact salt-bridged structures are also a requirement for effective niECD.
Subject(s)
Gases , Tandem Mass Spectrometry , Gases/chemistry , Tandem Mass Spectrometry/methods , Electrons , Anions/chemistry , Peptides/chemistry , Cations , Sodium ChlorideABSTRACT
We synthesize four novel quasi-one-dimensional organic-inorganic hybrid iron chloride compounds (CH3NH3FeCl3, CH(NH2)2FeCl3, C(NH2)3FeCl3, and C3H5N2FeCl3) and characterize their structural and magnetic properties. These materials crystallize in a hexagonal perovskite-type structure, constituting a triangular array of face-sharing iron chloride octahedra chains running along the c-axis, isolated from one another by the organic cation. Through magnetization and heat capacity measurements, we find that the intrachain coupling is weakly ferromagnetic for each variant. Importantly, this work underscores the utility of solid-state chemistry approaches in synthesizing new organic-inorganic hybrid materials.
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The morbidity associated with pediatric medulloblastoma, in particular in patients who develop leptomeningeal metastases, remains high in the absence of effective therapies. Administration of substances directly into the cerebrospinal fluid (CSF) is one approach to circumvent the blood-brain barrier and focus delivery of drugs to the site of tumor. However, high rates of CSF turnover prevent adequate drug accumulation and lead to rapid systemic clearance and toxicity. Here, we show that PLA-HPG nanoparticles, made with a single-emulsion, solvent evaporation process, can encapsulate talazoparib, a PARP inhibitor (BMN-673). These degradable polymer nanoparticles improve the therapeutic index when delivered intrathecally and lead to sustained drug retention in the tumor as measured with PET imaging and fluorescence microscopy. We demonstrate that administration of these particles into the CSF, alone or in combination with systemically administered temozolomide, is a highly effective therapy for tumor regression and prevention of leptomeningeal spread in xenograft mouse models of medulloblastoma. These results provide a rationale for harnessing nanoparticles for the delivery of drugs limited by brain penetration and therapeutic index and demonstrate important advantages in tolerability and efficacy for encapsulated drugs delivered locoregionally.
Subject(s)
Antineoplastic Agents , Cerebellar Neoplasms , Medulloblastoma , Nanoparticles , Child , Humans , Mice , Animals , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use , Medulloblastoma/drug therapy , Antineoplastic Agents/therapeutic use , Cerebellar Neoplasms/drug therapy , Cerebrospinal FluidABSTRACT
BACKGROUND: Recent large-scale sequencing efforts have shed light on the genetic contribution to the etiology of congenital heart defects (CHD); however, the relative impact of genetics on clinical outcomes remains less understood. Outcomes analyses using genetics are complicated by the intrinsic severity of the CHD lesion and interactions with conditionally dependent clinical variables. METHODS: Bayesian Networks were applied to describe the intertwined relationships between clinical variables, demography, and genetics in a cohort of children with single ventricle CHD. RESULTS: As isolated variables, a damaging genetic variant in a gene related to abnormal heart morphology and prolonged ventilator support following stage I palliative surgery increase the probability of having a low Mental Developmental Index (MDI) score at 14 months of age by 1.9- and 5.8-fold, respectively. However, in combination, these variables act synergistically to further increase the probability of a low MDI score by 10-fold. The absence of a damaging variant in a known syndromic CHD gene and a shorter post-operative ventilator support increase the probability of a normal MDI score 1.7- and 2.4-fold, respectively, but in combination increase the probability of a good outcome by 59-fold. CONCLUSIONS: Our analyses suggest a modest genetic contribution to neurodevelopmental outcomes as isolated variables, similar to known clinical predictors. By contrast, genetic, demographic, and clinical variables interact synergistically to markedly impact clinical outcomes. These findings underscore the importance of capturing and quantifying the impact of damaging genomic variants in the context of multiple, conditionally dependent variables, such as pre- and post-operative factors, and demography.
Single ventricle congenital heart disease is a birth defect. In these children, the heart has only one effective blood-pumping chamber instead of two. Surgery can reroute the blood to use only one chamber, but multiple risk factors influence how well a child develops afterwards. Studying these risk factors can be challenging because they are interconnected, i.e. children with a genetic birth defect may be more likely to have a lower birthweight, and hence more likely to spend longer in hospital after surgery. Here, we used a statistical approach not commonly applied to study congenital heart disease and describe that whether a genetic variant (a small difference in a child's DNA) is important for how a child with single ventricle heart disease develops and grows after surgery depends on the presence of other risk factors.
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An inhalable platform for messenger RNA (mRNA) therapeutics would enable minimally invasive and lung-targeted delivery for a host of pulmonary diseases. Development of lung-targeted mRNA therapeutics has been limited by poor transfection efficiency and risk of vehicle-induced pathology. Here, we report an inhalable polymer-based vehicle for delivery of therapeutic mRNAs to the lung. We optimized biodegradable poly(amine-co-ester) (PACE) polyplexes for mRNA delivery using end-group modifications and polyethylene glycol. These polyplexes achieved high transfection of mRNA throughout the lung, particularly in epithelial and antigen-presenting cells. We applied this technology to develop a mucosal vaccine for severe acute respiratory syndrome coronavirus 2 and found that intranasal vaccination with spike protein-encoding mRNA polyplexes induced potent cellular and humoral adaptive immunity and protected susceptible mice from lethal viral challenge. Together, these results demonstrate the translational potential of PACE polyplexes for therapeutic delivery of mRNA to the lungs.
Subject(s)
COVID-19 , Nanoparticles , Animals , Mice , Polymers , RNA, Messenger/genetics , COVID-19/prevention & control , Lung , VaccinationABSTRACT
We consider two-dimensional honeycomb-lattice topological insulators of electrons which are exposed to exchange couplings at the edges, paying particular attention to the energy dispersions of edge states. The energy band structure of edge states is found to depend strongly on the direction of exchange couplings. Energy band splitting occurs for the exchange couplings perpendicular to the plane of topological insulators. In contrast, the parallel exchange couplings turn out to generate a finite energy gap in the edge-state bands for zigzag edges while armchair nanoribbons does not show such energy gaps. We also discuss the dependence of energy band structures of edge states on the magnetic structure of exchange couplings as well as the disorder effects on the edge-state density of states.
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It is well documented that memory is heritable and that older adults tend to have poorer memory performance than younger adults. However, whether the magnitudes of genetic and environmental contributions to late-life verbal episodic memory ability differ from those at earlier ages remains unresolved. Twins from 12 studies participating in the Interplay of Genes and Environment in Multiple Studies (IGEMS) consortium constituted the analytic sample. Verbal episodic memory was assessed with immediate word list recall (N = 35,204 individuals; 21,792 twin pairs) and prose recall (N = 3,805 individuals; 2,028 twin pairs), with scores harmonized across studies. Average test performance was lower in successively older age groups for both measures. Twin models found significant age moderation for both measures, with total inter-individual variance increasing significantly with age, although it was not possible definitively to attribute the increase specifically to either genetic or environmental sources. Pooled results across all 12 studies were compared to results where we successively dropped each study (leave-one-out) to assure results were not due to an outlier. We conclude the models indicated an overall increase in variance for verbal episodic memory that was driven by a combination of increases in the genetic and nonshared environmental parameters that were not independently statistically significant. In contrast to reported results for other cognitive domains, differences in environmental exposures are comparatively important for verbal episodic memory, especially word list learning.
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This scientific statement from the American Heart Association focuses on treatment strategies and modalities for cardiomyopathy (heart muscle disease) in children and serves as a companion scientific statement for the recent statement on the classification and diagnosis of cardiomyopathy in children. We propose that the foundation of treatment of pediatric cardiomyopathies is based on these principles applied as personalized therapy for children with cardiomyopathy: (1) identification of the specific cardiac pathophysiology; (2) determination of the root cause of the cardiomyopathy so that, if applicable, cause-specific treatment can occur (precision medicine); and (3) application of therapies based on the associated clinical milieu of the patient. These clinical milieus include patients at risk for developing cardiomyopathy (cardiomyopathy phenotype negative), asymptomatic patients with cardiomyopathy (phenotype positive), patients with symptomatic cardiomyopathy, and patients with end-stage cardiomyopathy. This scientific statement focuses primarily on the most frequent phenotypes, dilated and hypertrophic, that occur in children. Other less frequent cardiomyopathies, including left ventricular noncompaction, restrictive cardiomyopathy, and arrhythmogenic cardiomyopathy, are discussed in less detail. Suggestions are based on previous clinical and investigational experience, extrapolating therapies for cardiomyopathies in adults to children and noting the problems and challenges that have arisen in this experience. These likely underscore the increasingly apparent differences in pathogenesis and even pathophysiology in childhood cardiomyopathies compared with adult disease. These differences will likely affect the utility of some adult therapy strategies. Therefore, special emphasis has been placed on cause-specific therapies in children for prevention and attenuation of their cardiomyopathy in addition to symptomatic treatments. Current investigational strategies and treatments not in wide clinical practice, including future direction for investigational management strategies, trial designs, and collaborative networks, are also discussed because they have the potential to further refine and improve the health and outcomes of children with cardiomyopathy in the future.
Subject(s)
Cardiomyopathies , Cardiomyopathy, Restrictive , Heart Diseases , Humans , American Heart Association , Cardiomyopathies/diagnosis , Cardiomyopathies/therapy , Cardiomyopathies/etiology , Heart Diseases/complications , Phenotype , ChildABSTRACT
BACKGROUND: Myocardial fibrosis, as diagnosed on cardiac magnetic resonance imaging (cMRI) by late gadolinium enhancement (LGE), is associated with adverse outcomes in adults with hypertrophic cardiomyopathy (HCM), but its prevalence and magnitude in children with HCM have not been established. We investigated: (1) the prevalence and extent of myocardial fibrosis as detected by LGE cMRI; (2) the agreement between echocardiographic and cMRI measurements of cardiac structure; and (3) whether serum concentrations of N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) and cardiac troponin-T are associated with cMRI measurements. METHODS: A cross-section of children with HCM from 9 tertiary-care pediatric heart centers in the U.S. and Canada were enrolled in this prospective NHLBI study of cardiac biomarkers in pediatric cardiomyopathy (ClinicalTrials.gov Identifier: NCT01873976). The median age of the 67 participants was 13.8 years (range 1-18 years). Core laboratories analyzed echocardiographic and cMRI measurements, and serum biomarker concentrations. RESULTS: In 52 children with non-obstructive HCM undergoing cMRI, overall low levels of myocardial fibrosis with LGE >2% of left ventricular (LV) mass were detected in 37 (71%) (median %LGE, 9.0%; IQR: 6.0%, 13.0%; range, 0% to 57%). Echocardiographic and cMRI measurements of LV dimensions, LV mass, and interventricular septal thickness showed good agreement using the Bland-Altman method. NT-proBNP concentrations were strongly and positively associated with LV mass and interventricular septal thickness (P < .001), but not LGE. CONCLUSIONS: Low levels of myocardial fibrosis are common in pediatric patients with HCM seen at referral centers. Longitudinal studies of myocardial fibrosis and serum biomarkers are warranted to determine their predictive value for adverse outcomes in pediatric patients with HCM.
Subject(s)
Cardiomyopathy, Hypertrophic , Contrast Media , Adult , Humans , Child , Infant , Child, Preschool , Adolescent , Prospective Studies , Gadolinium , Cardiomyopathy, Hypertrophic/diagnostic imaging , Fibrosis , Biomarkers , Magnetic Resonance Imaging, Cine , Myocardium/pathologyABSTRACT
Conventional approaches for screening anticancer drugs rely on chemical reactions, which are time consuming, labor intensive, and costly. Here, we present a protocol for label-free and high-throughput assessment of drug efficacy using a vision transformer and a Conv2D. We describe the steps for cell culture, drug treatment, data collection, and preprocessing. We then detail the building of deep learning models and their use to predict drug potency. This protocol can be adapted for screening chemicals that affect the density or morphological features of cells. For complete details on the use and execution of this protocol, please refer to Wang et al.1.
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As a measure of cytotoxic potency, half-maximal inhibitory concentration (IC50) is the concentration at which a drug exerts half of its maximal inhibitory effect against target cells. It can be determined by various methods that require applying additional reagents or lysing the cells. Here, we describe a label-free Sobel-edge-based method, which we name SIC50, for the evaluation of IC50. SIC50 classifies preprocessed phase-contrast images with a state-of-the-art vision transformer and allows for the continuous assessment of IC50 in a faster and more cost-efficient manner. We have validated this method using four drugs and 1,536-well plates and also built a web application. We anticipate that this method will assist in the high-throughput screening of chemical libraries (e.g., small-molecule drugs, small interfering RNA [siRNA], and microRNA and drug discovery).
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BACKGROUND: Subjective cognitive complaints (SCCs) may be a precursor to mild cognitive impairment (MCI) and dementia. OBJECTIVE: This study aimed to examine the heritability of SCCs, correlations between SCCs and memory ability, and the influence of personality and mood on these relationships. METHODS: Participants were 306 twin pairs. The heritability of SCCs and the genetic correlations between SCCs and memory performance, personality, and mood scores were determined using structural equation modelling. RESULTS: SCCs were low to moderately heritable. Memory performance, personality and mood were genetically, environmentally, and phenotypically correlated with SCCs in bivariate analysis. However, in multivariate analysis, only mood and memory performance had significant correlations with SCCs. Mood appeared to be related to SCCs by an environmental correlation, whereas memory performance was related to SCCs by a genetic correlation. The link between personality and SCCs was mediated by mood. SCCs had a significant amount of both genetic and environmental variances not explained by memory performance, personality, or mood. CONCLUSION: Our results suggest that SCCs are influenced both by a person's mood and their memory performance, and that these determinants are not mutually exclusive. While SCCs had genetic overlap with memory performance and environmental association with mood, much of the genetic and environmental components that comprised SCCs were specific to SCCs, though these specific factors are yet to be determined.