A Post-Hoc Analysis of Emotional Lability With Delayed-Release/Extended-Release Methylphenidate in Children Aged 6 to 12 Years of Age Participating in Two Phase 3 Clinical Trials.

OBJECTIVE: DR/ER-MPH (formerly HLD200) is an evening-dosed delayed-release and extended-release methylphenidate approved for the treatment of ADHD in patients ≥6 years. Post hoc analyses of two pivotal Phase 3 trials: HLD200-107 (NCT02493777) and HLD200-108 (NCT02520388) evaluated emotional lability (EL) with DR/ER-MPH treatment. METHODS: Differences in Conners Global Index-Parent (CGI-P) EL subscale scores and age- and gender-adjusted T-scores over an open-label titration phase (HLD200-107) and between treatment and placebo groups at endpoint (HLD200-108) were evaluated. RESULTS: In HLD200-107 (N = 117) mean CGI-P EL subscale scores improved from 5.3 to 1.3 (p < .0001) after 6 weeks; in HLD200-108 significant improvements were observed in the treatment group (n = 81) versus placebo (n = 80; 3.11 vs. 4.08; p = .0053). T-scores showed an improvement with DR/ER-MPH treatment in both trials. Few emotional adverse events (AEs) were reported. CONCLUSION: DR/ER-MPH treatment resulted in statistically significant improvements in EL to the level of non-ADHD peers as contextualized by T-scores.

Clinically Meaningful Improvements in Early Morning and Late Afternoon/Evening Functional Impairment in Children with ADHD Treated with Delayed-Release and Extended-Release Methylphenidate.

OBJECTIVE: The Before School Functioning Questionnaire and Parent Rating of Evening and Morning Behavior-Revised assess early morning (BSFQ, PREMB-R AM subscale) and late afternoon/evening (PREMB-R PM subscale) functional impairment in children with ADHD. Clinically meaningful improvements were identified and applied to a trial of delayed-release and extended-release methylphenidate (DR/ER-MPH) in children with ADHD (NCT02520388) to determine if the statistically-determined improvements in functional impairment were also clinically meaningful. METHOD: Clinically meaningful improvements in BSFQ/PREMB-R were established post hoc by receiver operating characteristics curves, using anchors of Clinical Global Impression-Improvement (CGI-I) = 1 and CGI-I ≤ 2. Percentages of participants achieving these thresholds were calculated. RESULTS: Thresholds for CGI-I = 1/CGI-I ≤ 2, respectively, were 27/20 (BSFQ), 5/3 (PREMB-R AM), and 9/5 (PREMB-R PM)-point decreases. More children achieved clinically meaningful improvements with DR/ER-MPH versus placebo (all p < .05). CONCLUSION: DR/ER-MPH increased proportions of children achieving clinically meaningful improvements in BSFQ and PREMB-R.

Symptomatic and Functional Response and Remission From the Open-Label Treatment-Optimization Phase of a Study With DR/ER-MPH in Children With ADHD.

Objective: Delayed-release and extended-release methylphenidate (DR/ER-MPH), the first stimulant predicted to be absorbed primarily in the colon, demonstrated significant improvements in attention-deficit/hyperactivity disorder (ADHD) symptoms and functional impairment from awakening until evening versus placebo in clinical trials. The clinical significance of these improvements was explored post hoc by examining response and remission thresholds as well as safety in the context of dose optimization.Methods: Data from the open-label, treatment-optimization phase of a phase 3 study of DR/ER-MPH in children (aged 6-12 years) with ADHD, as diagnosed by DSM-5 criteria and enrolled between July 2015 and March 2016, were analyzed. Thresholds for response (anchored to Clinical Global Impressions-Improvement scale [CGI-I] score of 1 or 2) and remission were applied to ADHD Rating Scale-IV (ADHD-RS-IV), Before School Functioning Questionnaire (BSFQ), and Parent Rating of Evening and Morning Behavior, Revised, Morning Subscale (PREMB-R AM) and Evening Subscale (PREMB-R PM) scores. Rates of response, remission, and treatment-emergent adverse events by starting dose were examined.Results: Mean DR/ER-MPH dose increased from 29.7 mg/d at baseline (51% on 20 mg/d; 49% on 40 mg/d) to 66.2 mg/d at week 6. At week 6, most participants achieved response/remission thresholds (response/remission: ADHD-RS-IV: 97%/89%; BSFQ: 98%/94%; PREMB-R AM: 94%/98%; PREMB-R PM: 91%/84%). More participants starting on a 40-mg versus 20-mg dose achieved thresholds at week 1 (P < .02). Weekly treatment-emergent adverse event rates over the open-label period were similar between starting doses.Conclusions: When DR/ER-MPH dosing was optimized for ADHD symptom control throughout the day, the majority of participants achieved thresholds indicating all-day control of ADHD symptoms and functional impairment to the level of their non-ADHD peers.Trial Registration: Data used in this post hoc analysis came from the study with ClinicalTrials.gov identifier: NCT02493777.

Effect of Delayed-Release and Extended-Release Methylphenidate on Caregiver Strain and Validation of Psychometric Properties of the Caregiver Strain Questionnaire: Results from a Phase 3 Trial in Children with Attention-Deficit/Hyperactivity Disorder.

Objectives: Inadequately controlled symptoms and associated impaired functioning have a significant negative impact on caregivers of children with attention-deficit/hyperactivity disorder (ADHD). This study aimed to assess the impact of evening-dosed, delayed-release and extended-release methylphenidate (DR/ER-MPH) treatment on caregiver strain, measured by the Caregiver Strain Questionnaire (CGSQ), and present post hoc psychometric analyses assessing the reliability and validity of the CGSQ, its ability to detect change (responsiveness), and to derive responder definitions. Methods: The CGSQ was an exploratory efficacy endpoint in a phase 3, 3-week, randomized, double-blind, multicenter, placebo-controlled, forced-dose titration trial of DR/ER-MPH in children aged 6-12 years with ADHD (NCT02520388). Psychometric properties of the CGSQ evaluated post hoc included internal consistency using Cronbach's alpha; test/retest reliability using intraclass correlation coefficients (ICCs); construct validity (known groups and convergent/divergent validity); responsiveness to changes in assessments of ADHD severity (ADHD Rating Scale-IV [ADHD-RS-IV], Conners' Global Index-Parent [CGI-P], and Clinical Global Impression-Severity [CGI-S]/CGI-Improvement [CGI-I]); and meaningful change threshold (MCT) using receiver operating characteristic curves, which were used to compare response between DR/ER-MPH and placebo groups. Results: Randomized DR/ER-MPH (54.5) and placebo (54.9) groups had similar mean CGSQ scores at screening. Caregivers of children on DR/ER-MPH reported significant reductions in CGSQ scores after 3 weeks of DR/ER-MPH treatment versus placebo (least-squares mean: 41.2 vs. 49.1; p < 0.001). The CGSQ demonstrated strong internal consistency (Cronbach's alpha = 0.93) and good test/retest reliability (ICC = 0.72). Known groups, convergent/divergent validity, and responsiveness were demonstrated from relationships between the CGSQ and the CGI-S, ADHD-RS-IV, and CGI-P. The mean anchor-based MCT for CGSQ total score was estimated as -9.0 (DR/ER-MPH vs. placebo: 53.2% vs. 29.9% p = 0.003). Conclusions: CGSQ scores significantly decreased after 3 weeks of DR/ER-MPH treatment versus placebo, and the CGSQ was found to be a valid and reliable measure of strain in caregivers of children with ADHD. Clinical trial registration identification number: NCT02520388.

Fragmentation and Matching of Human MicroRNA Sequences in 3'utr.

AIMS: Definition of sense and antisense microRNA matches in 3'utr. BACKGROUND: Matches of mature microRNAs (m-miRs) in human 3'utr could be traced to mutations producing fragments of original m-miR sequences without physical separation. (The m-miR matches in 5'utr and cds should be by far fewer, but could follow similar patterns). OBJECTIVE: To ascertain if the sense and antisense m-miR fragments in 3'utr occur at similar or different levels. METHODS: Frequency of sense and antisense m-miR matches in 3'utr was examined in the range of 7-22 nucleotides. RESULTS: The fragmentation occurs at gene level by mutation within one of the paired m-miRs, which upon transcription results in increased interactive capability for both former pre-micro (premir) RNA stem partners. The non-mutated stem partner can persist in 3'utr sequences, as is apparent from significant presence of miR-619-5p and miR-5096 and some conservation of 20 other simian- specific m-miR sequences. However, most of m-mir sequences in 3'utr are extensively fragmented, with low preservation of long matches. In flanks of individual m-miR embeds the mutated pre-mir positions are to a degree defined specifically. CONCLUSION: The m-mir matches of various sizes in 3'utr apparently reflect accumulation, on a phylogenetic time scale, of in-sequence point mutations. Across human 3'utr this fragmentation is significantly less for evolutionarily recent human m-miRs that originate in simians compared to human m-miRs first appearing in lower primates, and especially to human m-miRs introduced in nonprimates.

A Randomized, Double-Blind, Placebo-Controlled Study of HLD200, a Delayed-Release and Extended-Release Methylphenidate, in Children with Attention-Deficit/Hyperactivity Disorder: An Evaluation of Safety and Efficacy Throughout the Day and Across Settings.

Objectives: HLD200, a once-daily, evening-dosed, delayed-release and extended-release methylphenidate (DR/ER-MPH), was designed to provide therapeutic effect beginning upon awakening and lasting into the evening. This pivotal, randomized, double-blind, multicenter, placebo-controlled, phase 3 trial assessed improvements in functional impairment across the day using multiple validated measures tailored for different settings and time of day in children (6-12 years) with attention-deficit/hyperactivity disorder (ADHD). Methods: Following a 6-week, open-label titration of DR/ER-MPH to an optimal dose (20, 40, 60, 80, or 100 mg/day) and dosing time (8:00 PM ±1.5 hours), participants were randomized to treatment-optimized DR/ER-MPH or placebo for 1 week. The primary endpoint was the model-adjusted average of postdose Swanson, Kotkin, Agler, M-Flynn, and Pelham Scale combined scores (SKAMP CS) over a 12-hour laboratory classroom day (8:00 AM to 8:00 PM). The key secondary endpoint was the Parent Rating of Evening and Morning Behavior-Revised, Morning (PREMB-R AM) subscale. Secondary/exploratory measures included the PREMB-R Evening (PREMB-R PM) subscale and Permanent Product Measure of Performance (Attempted [PERMP-A] and Correct [PERMP-C]). Safety endpoints included treatment-emergent adverse events (TEAEs). Results: After the treatment-optimization phase, the mean optimized dose was 66.2 mg and the most common prescribed dosing time was 8:00 PM. Double-blind DR/ER-MPH treatment significantly improved functional impairment versus placebo in the early morning (PREMB-R AM: p < 0.001), averaged over the classroom day (SKAMP CS: p < 0.001), and in the late afternoon/evening (PREMB-R PM: p = 0.003) in the intent-to-treat population (N = 117). Average PERMP-A (p = 0.006) and PERMP-C (p = 0.009) also indicated improved classroom performance with DR/ER-MPH versus placebo. In the double-blind phase, TEAEs did not differ between DR/ER-MPH and placebo groups and no serious TEAEs or TEAEs leading to discontinuation were reported. Conclusion: DR/ER-MPH was well tolerated and demonstrated significant improvements versus placebo in functional impairment throughout the day across different settings in children with ADHD.

Pharmacokinetics of HLD200, a Delayed-Release and Extended-Release Methylphenidate: Evaluation of Dose Proportionality, Food Effect, Multiple-Dose Modeling, and Comparative Bioavailability with Immediate-Release Methylphenidate in Healthy Adults.

OBJECTIVES: HLD200, an oral, once-daily, evening-dosed, delayed-release, and extended-release methylphenidate (DR/ER-MPH), was designed to provide efficacy from the early morning, throughout the day, and into the evening to individuals with attention-deficit/hyperactivity disorder. The objectives were to evaluate DR/ER-MPH pharmacokinetic (PK) properties in healthy adults, including dose proportionality, food effect, the potential of accumulation using multiple-dose modeling, and bioavailability compared to an immediate-release MPH (IR MPH). METHODS: Three open-label, single-dose, crossover studies were conducted, all with a 7-day washout between treatments. In Study I, 20 subjects received evening-dosed DR/ER-MPH (20 and 100 mg) followed by a medium-fat breakfast; 13 subjects received a subsequent 100-mg dose of DR/ER-MPH followed by a low-fat breakfast. In Study II, 18 subjects were evaluated after receiving evening-dosed DR/ER-MPH (100 mg) under 3 conditions: immediately after a high-fat meal, sprinkled on applesauce, and in a fasted state. In Study III, 11 and 12 subjects received evening-dosed DR/ER-MPH (100 mg) and morning-dosed IR MPH (20 mg), respectively. RESULTS: DR/ER-MPH demonstrated dose proportionality between 20- and 100-mg doses. DR/ER-MPH PK parameters were not significantly affected by breakfast content or by sprinkling capsule contents. A high-fat meal immediately preceding evening dosing did not affect total MPH exposure but lowered peak MPH exposure by 14% and 11% versus fasted and sprinkled states, and time to peak exposure was delayed by ∼2.5 hours; these PK differences are unlikely to be clinically significant. Based on multiple-dose simulations using data from Study I, negligible accumulation of DR/ER-MPH was predicted. The relative bioavailability for DR/ER-MPH compared to IR MPH was 73.9%. No serious adverse events (AEs) were reported, and the observed AEs were consistent with MPH. There were no discontinuations in Studies I and III, but three participants withdrew in Study II due to AEs. CONCLUSIONS: Evening-dosed DR/ER-MPH demonstrated dose proportionality and can be administered with or without food. Significant accumulation is unlikely with multiple dosing.

The Expansion Segments of 28S Ribosomal RNA Extensively Match Human Messenger RNAs.

Eukaryote ribosomal RNAs (rRNAs) have expanded in the course of phylogeny by addition of nucleotides in specific insertion areas, the expansion segments. These number about 40 in the larger (25-28S) rRNA (up to 2,400 nucleotides), and about 12 in the smaller (18S) rRNA (<700 nucleotides). Expansion of the larger rRNA shows a clear phylogenetic increase, with a dramatic rise in mammals and especially in hominids. Substantial portions of expansion segments in this RNA are not bound to ribosomal proteins, and may engage extraneous interactants, including messenger RNAs (mRNAs). Studies on the ribosome-mRNA interaction have focused on proteins of the smaller ribosomal subunit, with some examination of 18S rRNA. However, the expansion segments of human 28S rRNA show much higher density and numbers of mRNA matches than those of 18S rRNA, and also a higher density and match numbers than its own core parts. We have studied that with frequent and potentially stable matches containing 7-15 nucleotides. The expansion segments of 28S rRNA average more than 50 matches per mRNA even assuming only 5% of their sequence as available for such interaction. Large expansion segments 7, 15, and 27 of 28S rRNA also have copious long (≥10-nucleotide) matches to most human mRNAs, with frequencies much higher than in other 28S rRNA parts. Expansion segments 7 and 27 and especially segment 15 of 28S rRNA show large size increase in mammals compared to other metazoans, which could reflect a gain of function related to interaction with non-ribosomal partners. The 28S rRNA expansion segment 15 shows very high increments in size, guanosine, and cytidine nucleotide content and mRNA matching in mammals, and especially in hominids. With these segments (but not with other 28S rRNA or any 18S rRNA expansion segments) the density and number of matches are much higher in 5'-terminal than in 3'-terminal untranslated mRNA regions, which may relate to mRNA mobilization via 5' termini. Matches in the expansion segments 7, 15, and 27 of human 28S rRNA appear as candidates for general interaction with mRNAs, especially those associated with intracellular matrices such as the endoplasmic reticulum.

Efficacy and Safety of HLD200, Delayed-Release and Extended-Release Methylphenidate, in Children with Attention-Deficit/Hyperactivity Disorder.

OBJECTIVE: Evening-dosed HLD200 is a delayed-release and extended-release methylphenidate (DR/ER-MPH) formulation consisting of uniform, dual-layered microbeads with an inner drug-loaded core. DR/ER-MPH is designed to delay the initial release of drug by 8-10 hours, and thereafter, provide a controlled, extended drug release to target onset of effect upon awakening that lasts into the evening. This phase 3 study evaluated the safety and efficacy of DR/ER-MPH on symptoms and temporal at-home functional impairment in children with attention-deficit/hyperactivity disorder (ADHD). METHODS: This 3-week, randomized, double-blind, multicenter, placebo-controlled, parallel-group, forced-dose titration trial evaluated DR/ER-MPH (40-80 mg/day) in children aged 6-12 years with ADHD. Primary efficacy endpoint was the ADHD rating scale-IV (ADHD-RS-IV), and the key secondary endpoints were the Before-School Functioning Questionnaire (BSFQ), and Parent Rating of Evening and Morning Behavior-Revised, morning (PREMB-R AM) and evening (PREMB-R PM). Safety measures included spontaneously reported treatment-emergent adverse events (TEAEs) and two TEAEs of special interest, appetite suppression and insomnia (with direct questioning on sleep disturbance). RESULTS: One hundred sixty-one participants were included in the intent-to-treat population (DR/ER-MPH, n = 81; placebo, n = 80). After 3 weeks, DR/ER-MPH achieved significant improvements versus placebo in ADHD symptoms (least-squares [LS] mean ADHD-RS-IV: 24.1 vs. 31.2; p = 0.002), and at-home early morning (LS mean BSFQ: 18.7 vs. 28.4; p < 0.001; LS mean PREMB-R AM: 2.1 vs. 3.6; p < 0.001) and late afternoon/evening (LS mean PREMB-R PM: 9.4 vs. 12.2; p = 0.002) functional impairment. Commonly reported TEAEs (≥10%) were insomnia and decreased appetite. CONCLUSIONS: DR/ER-MPH was generally well tolerated and demonstrated significant improvements versus placebo in ADHD symptoms and at-home functional impairments in the early morning, late afternoon, and evening in children with ADHD.

Canonical microRNA Matching Differs Greatly Across Groups of G-protein Coupled Receptor mRNAs.

BACKGROUND: Heptahelical G protein coupled receptors (GPCRs) support numerous sensory and metabolic functions and differ considerably in levels of expression. GPCR protein levels should link to regulation of GPCR mRNAs by microRNAs (miRs), which might significantly depend on numbers, size and GC content of the canonical antisense matches in mRNAs. These parameters of GPCR mRNAs have not been studied in detail. METHODS: Canonical matching profiles of human GPCR mRNAs and miRs were examined using segments of 7-15 nucleotides in windows shifted by one position over the entire microRNA sequence. RESULTS: Human GPCRs mRNAs within larger function-related groups have a quite homogenous matching with miRs. Both the GC content and the melting temperature (and hence also the binding energy) are appreciably higher in 5'utr compared to 3'utr matches of the same length. Increase in the GC content correlates significantly with length in the ubiquitous matches of 7-12 nucleotides. However, several GPCR groups strongly differ in overall match numbers and density. The untranslated regions of sensory receptor mRNAs, especially the olfactory and Taste-2 mRNAs, have the lowest match numbers and density and the fewest miR partners. The glucagon and frizzled families show the highest canonical matching. CONCLUSION: Partnership of GPCR mRNAs and miRs could significantly relate to the type of function of the receptor proteins, with mRNAs of the sensory receptors having the lowest and those of metabotropic GPCRs the highest targeting. This could be of interest regarding GPCR regulation by exogenous miRs.

Cue-dependent inhibition in posttraumatic stress disorder and attention-deficit/hyperactivity disorder.

OBJECTIVE: Attention-deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD) are common among military veterans, but the comorbidity of these two psychiatric disorders remains largely unstudied. Evaluating response inhibition and cue-dependent learning as behavioral and neurocognitive mechanisms underlying ADHD/PTSD can inform etiological models and development of tailored interventions. METHOD: A cued go/no-go task evaluated response inhibition in 160 adult males. Participants were recruited from the community and a Veterans Administration medical center. Four diagnostic groups were identified: ADHD-only, PTSD-only, ADHD+PTSD, controls. RESULTS: Group differences were observed across most indices of inhibitory functioning, reaction time, and reaction time variability, whereby PTSD-only and ADHD+PTSD participants demonstrated deficits relative to controls. No cue dependency effects were observed. CONCLUSION: Finding complement prior work on neurocognitive mechanisms underlying ADHD, PTSD, and ADHD+PTSD. Lack of expected group differences for the ADHD-only group may be due to limited power. Additional work is needed to better characterize distinctions among clinical groups, as well as to test effects among women and youth.

Effect of Food Intake on the Pharmacokinetics of a Novel Methylphenidate Extended-Release Oral Suspension for Attention Deficit Hyperactivity Disorder.

We conducted an open-label, single-dose, randomized, crossover study in healthy adults to assess the impact of food on the bioavailability of 60 mg methylphenidate extended-release oral suspension (MEROS; Quillivant XR™)-a long-acting stimulant for the treatment of attention deficit hyperactivity disorder-by comparing the pharmacokinetic parameters under fed and fasting conditions. When MEROS 60 mg was administered under fed conditions compared with fasting conditions, the exposure of methylphenidate (d enantiomer) was higher, with a mean area under the plasma concentration-vs-time curve (AUC)0-t of 160.2 ng·h/mL vs 140.4 ng·h/mL, and a mean AUC0-inf of 163.2 ng·h/mL vs 143.7 ng·h/mL, respectively. The ratios of the ln-transformed geometric means for methylphenidate for AUC0-t and AUC0-inf were 119.5% (90%CI, 115.7% to 123.5%) and 119.0% (90%CI, 115.2% to 122.8%), respectively, within the standard 80% to 125% bioequivalence acceptance range indicating no food effect on the overall exposure (rate and extent). There was a small increase in the peak plasma concentration (127.6% [90%CI, 119.9% to 135.8%]). However, this effect was small and not likely to be clinically significant. Overall, MEROS 60 mg was safe in both the fed and fasting condition when administered to healthy volunteers in this study.

Canonical Matches of Human MicroRNAs with mRNAs: A Broad Matrix of Position and Size.

BACKGROUND: Canonical hydrogen-bonding multi-nucleotide matches of microRNAs (miRs) with mRNAs are considered as important in mRNA regulation. MiR "seed" positions 2-8 are frequently viewed as mRNA partners, but there is ample evidence for use of other (and even non-contiguous) miR parts. No detailed information is available about canonical matching, and the GC content of the matches is rarely considered, although it should have a major regulatory potential. METHODS: Sequences of 2586 human miRs and of 5'utr, cds and 3'utr in 18810 human mRNAs were examined for number and GC content of contiguous Watson-Crick antisense matches of six or more nucleotides (nt) in successive windows shifted by 1 nt. RESULTS: Frequency of the antisense matches is within all sectors similar for segments of up to 10 nt starting at positions 1-10 of miR sequences, with decrease of 3.5 to 4-fold for each 1-nt increment. Adenine and uracil rich elements (ARE-like) are very frequent in cds and 3'utr. All mRNAs have matches of up to 10 nt, and most also those of 11-15 nt. The match density is largest in 5'utr, and the match number in cds. The 5'utr and cds matches average much higher GC content than those of 3'utr. The GC content of matches is above that for the whole sector in 5'utr and cds, but lower in 3'utr. CONCLUSION: Human mRNA matches across miR sequences constitute a positionally similar matrix of canonical hydrogen-bonding reactivity. This presents ample opportunities for contiguous binding independent of miR position. The ubiquitous 10 to 15-nt matches could serve as binding foci. Interaction of miRs with the abundant GC-rich 5'utr and cds counterparts could be important in the regulation of mRNA-ribosome interaction as well as in mRNA disposal. The lower density and GC content of a majority of 3'utr matches could mainly support a dynamic regulation by miRs.

Homoiterons and expansion in ribosomal RNAs.

Ribosomal RNAs in both prokaryotes and eukaryotes feature numerous repeats of three or more nucleotides with the same nucleobase (homoiterons). In prokaryotes these repeats are much more frequent in thermophile compared to mesophile or psychrophile species, and have similar frequency in both large RNAs. These features point to use of prokaryotic homoiterons in stabilization of both ribosomal subunits. The two large RNAs of eukaryotic cytoplasmic ribosomes have expanded to a different degree across the evolutionary ladder. The big RNA of the larger subunit (60S LSU) evolved expansion segments of up to 2400 nucleotides, and the smaller subunit (40S SSU) RNA acquired expansion segments of not more than 700 nucleotides. In the examined eukaryotes abundance of rRNA homoiterons generally follows size and nucleotide bias of the expansion segments, and increases with GC content and especially with phylogenetic rank. Both the nucleotide bias and frequency of homoiterons are much larger in metazoan and angiosperm LSU compared to the respective SSU RNAs. This is especially pronounced in the tetrapod vertebrates and seems to culminate in the hominid mammals. The stability of secondary structure in polyribonucleotides would significantly connect to GC content, and should also relate to G and C homoiteron content. RNA modeling points to considerable presence of homoiteron-rich double-stranded segments especially in vertebrate LSU RNAs, and homoiterons with four or more nucleotides in the vertebrate and angiosperm LSU RNAs are largely confined to the expansion segments. These features could mainly relate to protein export function and attachment of LSU to endoplasmic reticulum and other subcellular networks.

G and C Iterons and Strings in MicroRNAs Should be Important in Regulation of mRNAs(†).

BACKGROUND: Same-nucleotide repeats (iterons) are strongly expressed in many DNA regions and RNA classes. These repeats serve importantly in association of polynucleotides and proteins, but have not been characterized in miRNAs. METHODS: Iterons and nucleotide strings were quantified in currently known human miRNAs, including some comparisons with miRNAs of other species. RESULTS: Human 5p miRNAs have significantly more G iterons than other miRNA groups. The 3p miRNAs have an inverse excess of C iterons. The miRNAs lacking functional counter-stems (which we differentiate as 5n or 3n by position in pre-miRNAs) also have a large excess of G iterons. In 5p miRNAs G and C iterons have much higher density in the seed compared to the post-seed region. This difference is lower in 5n and 3n sequences, and much lower in 3p sequences. In all groups the contiguous GC strings constitute a larger part of sequences than the AU strings. A surplus of G or C iterons and of GC strings should enable a more stable association with the target mRNAs. CONCLUSION: From the available evidence, the G iteron- and GC-rich miRNAs should also interact more readily with miRNA-processing and similar proteins.

Emotional Lability in Patients with Attention-Deficit/Hyperactivity Disorder: Impact of Pharmacotherapy.

Attention-deficit/hyperactivity disorder (ADHD) is a neurobehavioral disorder defined by persistent inattention and/or hyperactivity and impulsivity. These symptoms occur more frequently and are more severe in individuals with ADHD compared with those at a similar developmental level without ADHD, and can be conceptualized as deficits in executive functioning (EF). EF includes domains of metacognition and inhibition, which influence the ability to regulate responses elicited by emotional stimuli. EF deficits can lead to emotional lability (EL), which is characterized by sudden changes in emotion and behaviors of inappropriately high intensity that may include sudden bouts of anger, dysphoria, sadness, or euphoria. EL is common and estimated to occur in about 3.3-10% of the population. Recent estimates of EL prevalence in children and adolescents with ADHD range from 38 to 75%. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition does not include EL in diagnostic criteria for ADHD, but does include ADHD-associated features of low frustration tolerance, irritability, or mood lability. The neurobiological basis of EL is not well understood, but brain imaging studies support dividing EF into "cool" cognitive networks encompassing attention and planning activities, and "hot" motivational networks involved in temporal discounting, reward processing, and reward anticipation. Dysfunction in "hot" networks is thought to be related to EL. EL symptoms are associated with more severe ADHD and co-morbidities, have significant impact on functioning, and may respond to treatment with medications frequently used to treat ADHD. Treatment outcomes and areas for future research are discussed.

Early Morning Functioning in Stimulant-Treated Children and Adolescents with Attention-Deficit/Hyperactivity Disorder, and its Impact on Caregivers.

OBJECTIVE: The purpose of this study was to examine the temporal occurrence and severity of inadequate attention-deficit/hyperactivity disorder (ADHD) symptom control throughout the day, and, more specifically, the frequency and severity of associated functional impairments and their apparent emotional impact on parents and caregivers during the early morning routine before school, in children and adolescents with ADHD currently treated with stable doses of stimulant medications. METHODS: Information was obtained from 201 primary caregivers of children and adolescents with ADHD using a self-administered, on-line quantitative research survey. RESULTS: Inadequately controlled ADHD symptoms were rated as most severe during the evening homework time and the early morning routine. The majority of caregivers reported early morning ADHD symptoms and impairment of early morning functioning (EMF) as moderate to severe. Caregiver reactions to their child's early morning ADHD symptoms and unwanted behaviors included feeling overwhelmed, exhausted, and constantly stressed. CONCLUSIONS: Control of EMF impairments from inadequately controlled ADHD symptoms is a significant unmet need in children and adolescents with ADHD treated with stable morning doses of stimulant medications. Current orally administered stimulant treatment options have not addressed this challenge.

Pozanicline for the treatment of attention-deficit/hyperactivity disorder.

INTRODUCTION: Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder occurring in childhood and often continues into adolescence and adulthood. The pathophysiology of ADHD is complex and likely involves multiple neurotransmitter systems. Medications currently used for the treatment of ADHD enhance dopaminergic and/or noradrenergic transmission. However, none of these drugs target the cholinergic system, which is also thought to play a significant role in cognitive disturbances such as those found in ADHD. AREAS COVERED: In this review, the authors briefly discuss the cholinergic system, including multiple neuronal nicotinic receptor (NNR) subtypes that mediate the positive and negative effects of nicotine, in the context of animal models of ADHD. They also discuss the pharmacology of the NNR pozanicline , a partial agonist with high in vitro binding affinity and selectivity for the α4ß2 NNR subtype. Finally, the authors examine pozanicline's clinical developments. EXPERT OPINION: Pozanicline was shown to be effective in a pilot study in humans with ADHD, but larger trials were negative. Developing an efficacious therapy is difficult. ADHD is a complex disorder with an unknown cause, and it is unclear, at this time, which qualities from NNR agonists are needed to treat it. It is therefore necessary to develop a more enhanced understanding of the nicotinic cholinergic system and its role in ADHD. Furthermore, new research paradigms may need to be employed to find drugs that are effective in patients with ADHD.

Dimers of G-protein coupled receptors as versatile storage and response units.

The status and use of transmembrane, extracellular and intracellular domains in oligomerization of heptahelical G-protein coupled receptors (GPCRs) are reviewed and for transmembrane assemblies also supplemented by new experimental evidence. The transmembrane-linked GPCR oligomers typically have as the minimal unit an asymmetric ~180 kDa pentamer consisting of receptor homodimer or heterodimer and a G-protein αßγ subunit heterotrimer. With neuropeptide Y (NPY) receptors, this assembly is converted to ~90 kDa receptor monomer-Gα complex by receptor and Gα agonists, and dimers/heteropentamers are depleted by neutralization of Gαi subunits by pertussis toxin. Employing gradient centrifugation, quantification and other characterization of GPCR dimers at the level of physically isolated and identified heteropentamers is feasible with labeled agonists that do not dissociate upon solubilization. This is demonstrated with three neuropeptide Y (NPY) receptors and could apply to many receptors that use large peptidic agonists.