Sleep in older adolescents. Results from a large cross-sectional, population-based study

Postponed access until 21.12.2021.The aim of the present study was to describe sleep patterns in a large and representative sample of Norwegian adolescents. The sample included 4,010 first-year high school students, aged 16–17 years (54% female), who completed a web-based survey on sleep patterns. The process of going to sleep was addressed as a two-step sequence of (a) shuteye latency (interval from bedtime to shuteye time) and (b) sleep onset latency (interval from shuteye time to sleep onset). Results showed that 84.8% of the adolescents failed to obtain the recommended amount of sleep (8+ h) on schooldays, and 49.4% obtained less than 7 h. Mean bedtime on schooldays was 10:33 PM, with rise time 8:19 h later (time in bed). The adolescents reported long school-day shuteye latency (43 min), limiting sleep opportunity to 7:36 h. Sleep onset latency was 32 min and mean school-day sleep duration was only 6:43 h. On free days, 26.3% of the adolescents obtained less than 8 h of sleep, and 11.7% obtained less than 7 h. Mean bedtime was 00:33 AM, time in bed was 10:35 h, shuteye latency was 39 min and sleep onset latency was 24 min. Mean free-day sleep duration was 8:38 h. There were sex differences in several sleep parameters, including shuteye latency. The results indicate that the majority of Norwegian adolescents fail to obtain the recommended amount of sleep (8+ h) on schooldays. Long shuteye latency appears to be a main driver for short school-day sleep duration in adolescents.acceptedVersio

Ghrelin receptor in GtoPdb v.2021.3

The ghrelin receptor (nomenclature as agreed by the NC-IUPHAR Subcommittee for the Ghrelin receptor [19]) is activated by a 28 amino-acid peptide originally isolated from rat stomach, where it is cleaved from a 117 amino-acid precursor (GHRL, Q9UBU3). The human gene encoding the precursor peptide has 83% sequence homology to rat prepro-ghrelin, although the mature peptides from rat and human differ by only two amino acids [74]. Alternative splicing results in the formation of a second peptide, [des-Gln14]ghrelin with equipotent biological activity [49]. A unique post-translational modification (octanoylation of Ser3, catalysed by ghrelin Ο-acyltransferase (MBOAT4, Q96T53) [133] occurs in both peptides, essential for full activity in binding to ghrelin receptors in the hypothalamus and pituitary, and for the release of growth hormone from the pituitary [58]. Structure activity studies showed the first five N-terminal amino acids to be the minimum required for binding [4], and receptor mutagenesis has indicated overlap of the ghrelin binding site with those for small molecule agonists and allosteric modulators of ghrelin function [44]. An endogenous antagonist and inverse agonist called Liver enriched antimicrobial peptide 2 (Leap2), expressed primarily in hepatocytes and in enterocytes of the proximal intestine [35, 68] inhibits ghrelin receptor-induced GH secretion and food intake [35]. The secretion of Leap2 and ghrelin is inversely regulated under various metabolic conditions [71]. In cell systems, the ghrelin receptor is constitutively active [45], but this is abolished by a naturally occurring mutation (A204E) that results in decreased cell surface receptor expression and is associated with familial short stature [93]

Ghrelin receptor (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

The ghrelin receptor (nomenclature as agreed by the NC-IUPHAR Subcommittee for the Ghrelin receptor [18]) is activated by a 28 amino-acid peptide originally isolated from rat stomach, where it is cleaved from a 117 amino-acid precursor (GHRL, Q9UBU3). The human gene encoding the precursor peptide has 83% sequence homology to rat prepro-ghrelin, although the mature peptides from rat and human differ by only two amino acids [70]. Alternative splicing results in the formation of a second peptide, [des-Gln14]ghrelin with equipotent biological activity [48]. A unique post-translational modification (octanoylation of Ser3, catalysed by ghrelin Ο-acyltransferase (MBOAT4, Q96T53) [127] occurs in both peptides, essential for full activity in binding to ghrelin receptors in the hypothalamus and pituitary, and for the release of growth hormone from the pituitary [56]. Structure activity studies showed the first five N-terminal amino acids to be the minimum required for binding [4], and receptor mutagenesis has indicated overlap of the ghrelin binding site with those for small molecule agonists and allosteric modulators of ghrelin function [43]. In cell systems, the ghrelin receptor is constitutively active [44], but this is abolished by a naturally occurring mutation (A204E) that results in decreased cell surface receptor expression and is associated with familial short stature [88]

Ghrelin receptor in GtoPdb v.2023.1

The ghrelin receptor (nomenclature as agreed by the NC-IUPHAR Subcommittee for the Ghrelin receptor [19]) is activated by a 28 amino-acid peptide originally isolated from rat stomach, where it is cleaved from a 117 amino-acid precursor (GHRL, Q9UBU3). The human gene encoding the precursor peptide has 83% sequence homology to rat prepro-ghrelin, although the mature peptides from rat and human differ by only two amino acids [75]. Alternative splicing results in the formation of a second peptide, [des-Gln14]ghrelin with equipotent biological activity [50]. A unique post-translational modification (octanoylation of Ser3, catalysed by ghrelin Ο-acyltransferase (MBOAT4, Q96T53) [134] occurs in both peptides, essential for full activity in binding to ghrelin receptors in the hypothalamus and pituitary, and for the release of growth hormone from the pituitary [59]. Structure activity studies showed the first five N-terminal amino acids to be the minimum required for binding [4], and receptor mutagenesis has indicated overlap of the ghrelin binding site with those for small molecule agonists and allosteric modulators of ghrelin function [45]. An endogenous antagonist and inverse agonist called Liver enriched antimicrobial peptide 2 (Leap2), expressed primarily in hepatocytes and in enterocytes of the proximal intestine [36, 69] inhibits ghrelin receptor-induced GH secretion and food intake [36]. The secretion of Leap2 and ghrelin is inversely regulated under various metabolic conditions [72]. In cell systems, the ghrelin receptor is constitutively active [46], but this is abolished by a naturally occurring mutation (A204E) that results in decreased cell surface receptor expression and is associated with familial short stature [94]

Sleep during COVID-19-related school lockdown, a longitudinal study among high school students

There has been great concern about the impact of coronavirus disease 2019 (COVID-19)-related school lockdown on adolescent health. The aim of the present study was to compare sleep patterns before and during COVID-19-related school lockdown, in a large sample of high school students. The present study is based a prospective, longitudinal survey on adolescent sleep health. Phase 1 was conducted in 2019, whereas phase 2 was conducted in 2020 (response rate 60.2%), during the last 10 days of a 60-day long school lockdown. Main outcomes comprised sleep parameters from the Munich ChronoType Questionnaire (MCTQ). A total of 2,022 students provided valid responses to MCTQ in both survey phases. Results showed later sleep timing on schooldays in 2020 compared to 2019 (36 min later bedtimes, Cohen’s d = 0.56; 1:35 hr later rise times, Cohen’s d = 1.44). Time spent in bed on schooldays increased from 8:20 to 9:19 hr (Cohen’s d = 0.78), and sleep duration increased by 45 min (Cohen’s d = 0.49). The proportion of adolescents obtaining the recommended ≥8 hr of sleep on schooldays increased from 13.4% (2019) to 37.5% during the lockdown. Social jetlag was reduced from 2:37 hr (2019) to 1:53 hr (2020, Cohen’s d = 0.59). Results points to a potential advantageous effect of school lockdown in terms of increased school day sleep duration and reduced social jetlag. As sleep is important for mental and somatic health, it is conceivable that increased sleep duration offered some protection against harmful aspects of the COVID-19 pandemic and associated social restrictions. Future studies should address possible associations between sleep changes and health during COVID-19-related school lockdown.publishedVersio

Synthetic cationic antimicrobial peptides bind with their hydrophobic parts to drug site II of human serum albumin

BACKGROUND: Many biologically active compounds bind to plasma transport proteins, and this binding can be either advantageous or disadvantageous from a drug design perspective. Human serum albumin (HSA) is one of the most important transport proteins in the cardiovascular system due to its great binding capacity and high physiological concentration. HSA has a preference for accommodating neutral lipophilic and acidic drug-like ligands, but is also surprisingly able to bind positively charged peptides. Understanding of how short cationic antimicrobial peptides interact with human serum albumin is of importance for developing such compounds into the clinics. RESULTS: The binding of a selection of short synthetic cationic antimicrobial peptides (CAPs) to human albumin with binding affinities in the μM range is described. Competitive isothermal titration calorimetry (ITC) and NMR WaterLOGSY experiments mapped the binding site of the CAPs to the well-known drug site II within subdomain IIIA of HSA. Thermodynamic and structural analysis revealed that the binding is exclusively driven by interactions with the hydrophobic moieties of the peptides, and is independent of the cationic residues that are vital for antimicrobial activity. Both of the hydrophobic moieties comprising the peptides were detected to interact with drug site II by NMR saturation transfer difference (STD) group epitope mapping (GEM) and INPHARMA experiments. Molecular models of the complexes between the peptides and albumin were constructed using docking experiments, and support the binding hypothesis and confirm the overall binding affinities of the CAPs. CONCLUSIONS: The biophysical and structural characterizations of albumin-peptide complexes reported here provide detailed insight into how albumin can bind short cationic peptides. The hydrophobic elements of the peptides studied here are responsible for the main interaction with HSA. We suggest that albumin binding should be taken into careful consideration in antimicrobial peptide studies, as the systemic distribution can be significantly affected by HSA interactions

Circadian typology and implications for adolescent sleep health. Results from a large, cross-sectional, school-based study

Study objectives To investigate circadian typology in a large, representative sample of Norwegian adolescents, and its implications for sleep health. Methods The sample included 3920 1st year high school students aged 16–17 years. Respondents completed a web-based survey, including the short version of the Horne-Ostberg Morningness-Eveningness Questionnaire (rMEQ), the Munich Chronotype Questionnaire (MCTQ) and items on sleep-related behaviors (eg electronic media usage in bed, consumption of caffeinated beverages), sleep beliefs and daytime sleepiness. Data were analyzed using one-way ANOVAs and Chi-squared tests. Results In all, 7.8% were categorized as morning, 52.3% as intermediate and 39.9% as evening types, respectively. Evening types had later sleep timing, longer sleep latency, more social jetlag and shorter school day sleep duration than morning types, with intermediate types displaying a sleep pattern between these two extremes. None of the circadian types met the minimum recommended amount of sleep on school nights (ie 8+ hours), and only morning types had a mean sleep duration of 7+ hours (7:19 h, nearly 1 h more than evening types who slept 6:20 h, p < 0.001). Evening types reported more use of electronic media in bed, more consumption of caffeinated beverages and more daytime sleepiness than the other circadian types. They were also less satisfied with their school day sleep duration and perceived it more difficult to change their sleep pattern. Conclusions Results from this study suggest that eveningness represents a sleep health challenge for older adolescents.publishedVersio

Differential associations between types of social media use and university students' non-suicidal self-injury and suicidal behavior

Under embargo until: 2022-11-2Objective To examine differential associations between types of social media use and non-suicidal self-injury (NSSI) and suicidal behaviors. Methods Participants were N = 40,065 Norwegian college and university students, age 18–25, from the 2018 Students' Health and Wellbeing (SHoT) study. Students reported on their use of social media for seven specific activities, which we categorized into active and passive non-social use, passive social use, active public social, and active private social use. We also considered students' tendency for negative social comparisons on social media. Outcomes were past-year NSSI, NSSI ideation, suicidal ideation, and suicide attempt. Covariates were age, gender, total daily screen time and financial stress. Results Results of multiple logistic regression revealed differential associations between types of social media use and outcomes. Notably, active social private use (e.g., messaging friends) was associated with decreased odds of all outcomes, whereas active social public use (e.g., status updates) was associated with increased odds of NSSI ideation, NSSI, and suicide attempt. Social comparison was associated with increased odds of all outcomes. Conclusion Our results suggest that specific types of social media use are differentially associated with NSSI and suicidal outcomes among university students.acceptedVersio