Mitochondria and Aging

Cover illustration: Mitochondria and Aging, a special issue edited by Professor Heinz D. Osiewacz (Frankfurt, Germany), devoted to aging research and the involvement of mitochondria “from models to humans”. Depicted are a 3D section of a human cell with mitochondria shown in red (© NIH, see http://ghr.nlm.nih.gov/handbook/illustrations/cellmitochondria) and from top to bottom: micrograph of mitochondria from the model organism Podospora anserina (© C. Scheckhuber, see p. 781), hand with pill (© Photodisc Inc.) and the worm Caenorhabditis elegans with typical senescent morphology (© B. Braeckman, see p. 803).     

Biotechnology in Asia

Cover illustration: The Asian Federation of Biotechnology (AFOB, http://www.afob.org ) was established to promote cooperation between all those interested in biotechnology in Asia and stimulate innovation and technology transfer with the goal of advancing biotechnology in Asia and the rest of the world. BTJ continues its cooperation with AFOB and Asian Congress on Biotechnology (ACB-2011), with a special issue of articles from selected invited speakers at the congress, edited by Jian-Jiang Zhong (Chair ACB-2011 Organizing Committee; SJTU, China), and Sang Yup Lee (BTJ's Editor-in-Chief; KAIST, Korea). Read the Editorial: http://dx.doi.org/10.1002/201100445     

Focus: Nutrigenomics

Cover illustration: Nutrigenomics aims to identify the genes that influence the risk of diet-related diseases on a genomewide scale, and to understand the mechanisms that underlie these genetic predispositions. This BTJ special issue edited by Taesun Park features articles uncovering ‘dietary signatures’ associated with obesity and metabolic diseases. Images copyright: Yellow, green, and red bell peppers. © Photodisc, Microarray; © http://genomics.energy.gov     

Effect of liposome-treated red blood cells in an anemic rat model

Context: Liposomes have been shown to improve human red blood cell (RBC) in vitro quality by minimizing membrane damage occurring during 42-d hypothermic storage. Small animal models are necessary to evaluate novel blood products and guide future clinical studies.

Objectives: The aim of this study was to assess the effect of liposome treatments on rat RBC hypothermic storage lesion (HSL) and to examine in vivo outcomes of transfusing liposome treated RBCs in a rat model.

Materials and methods: Unilamellar liposomes were synthesized which contained saturated (DPPC:CHOL, 7:3?mol%), unsaturated (DOPC:CHOL, 7:3?mol%), saturated charged (DPPC:CHOL:PS, 6:3:1?mol%), and unsaturated charged (DOPC:CHOL:PS, 6:3:1?mol%) phospholipids. After liposome treatment, rat RBC quality was assessed by percent hemolysis, deformability, aggregation, hematological indices, microvesiculation, and cholesterol/phospholipid concentrations. An anemic rat model of myocardial ischemia and reperfusion (I/R) was used to evaluate the outcomes of transfusing liposome-treated RBCs.

Results: All four liposome treatments resulted in significant decreases in hemolysis, with the most prominent effect seen with DOPC-liposomes (DOPC: 1.6?±?0.1% versus control: 3.1?±?0.2%, p?=?0.015). RBCs treated with uncharged liposomes had lower hemolysis compared with charged liposomes (3.4?±?0.2% versus 3.9?±?0.4%, p?=?0.010). The in vivo study showed no significant difference in the hemoglobin levels and infarct size (53.3?±?13.1% versus 45.3?±?8.4%, p?=?0.223) between liposome and control groups.

Discussion and conclusion: Liposome treatment improved in vitro quality of stored rat RBCs. However, the changes observed in vitro were not sufficient to improve the in vivo outcomes of myocardial I/R in anemic rats transfused with liposome-treated RBCs.     

Bright light exposure before bedtime impairs response inhibition the following morning: a non-randomized crossover study

Introduction: Bright light exposure in the late evening can affect cognitive function the following morning either by changing the biological clock and/or disturbing sleep, but the evidence for this effect is scarce, and the underlying mechanism remains unknown. In this study, we first aimed to evaluate the effect of bright light exposure before bedtime on frontal lobe activity the following morning using near-infrared spectroscopy (NIRS) during a Go/NoGo task. Second, we aimed to evaluate the effects of bright light exposure before bedtime on polysomnographic measures and on a frontal lobe function test the following morning.

Methods: Twenty healthy, young males (mean age, 25.5 years) were recruited between September 2013 and August 2014. They were first exposed to control light (150 lux) before bedtime (from 20:00 h to 24:00 h) for 2 days and then to bright light (1,000 lux) before bedtime for an additional 5 days. We performed polysomnography (PSG) on the final night of each light exposure period (on nights 2 and night 7) and performed NIRS, which measures the concentrations of oxygenated and deoxygenated hemoglobin (OxyHb and DeoxyHb, respectively), coupled with a Go/NoGo task the following morning (between 09:30 h and 11:30 h). The participants also completed frontal lobe function tests the following morning.

Results: NIRS showed decreased hemodynamic activity (lower OxyHb and a tendency toward higher DeoxyHb concentration) in the right frontal lobe during the NoGo block after 1000-lux light exposure compared with that during the NoGo block after 150-lux light exposure. The commission error rate (ER) during the Go/NoGo task was higher after 1000-lux light exposure than that during the Go/NoGo task after 150-lux light exposure (1.24 ± 1.09 vs. 0.6 ± 0.69, P = 0.002), suggesting a reduced inhibitory response.

Conclusion: This study shows that exposure to bright light before bedtime for 5 days impairs right frontal lobe activation and response inhibition the following morning.     

A comparison of HMGB1 concentrations between cerebrospinal fluid and blood in patients with neurological disease

Aims: To determine whether a correlation exists between paired cerebrospinal fluid (CSF) and serum levels of a novel inflammatory biomarker, high-mobility group box 1 (HMGB1), in different neurological conditions.

Methods: HMGB1 was measured in the serum and CSF of 46 neurological patients (18 idiopathic intracranial hypertension [IIH], 18 neurological infection/inflammation [NII] and 10 Rasmussen’s encephalitis [RE]).

Results: Mean serum (±?SD) HMGB1 levels were 1.43?±?0.54, 25.28?±?27.9 and 1.89?±?1.49?ng/ml for the patients with IIH, NII and RE, respectively. Corresponding mean (±?SD) CSF levels were 0.35?±?0.22, 4.48?±?6.56 and 2.24?±?2.35?ng/ml. Both CSF and serum HMGB1 was elevated in NII. Elevated CSF HMGB1 was demonstrated in RE. There was no direct correlation between CSF and serum levels of HMGB1.

Conclusion: Serum HMGB1 cannot be used as a surrogate measure for CSF levels. CSF HMGB1 was elevated in NII and RE, its role as a prognostic/stratification biomarker needs further study.     

High inter-individual variability of serum xanthine oxidoreductase activity in IBD patients

Objectives: Thiopurines play an essential role in the management of inflammatory bowel diseases (IBD, i.e. Crohn's disease and ulcerative colitis). Over the past decade, several strategies to optimize treatment with thiopurines have been evaluated, including co-administration of allopurinol, a xanthine-oxidoreductase (XO) inhibitor, to low-dose thiopurine therapy. We aimed to assess the inter-individual variability of XO-activity between IBD-patients.

Methods: We assessed XO activity in serum of IBD-patients of two medical centers in The Netherlands using the Amplex® Red Xanthine/Xanthine Oxidase Assay Kit, which measures the superoxide formation in a coupled reaction to the red-fluorescent oxidation product, resofurine.

Results: We observed a high inter-individual variability of XO-activity in 119 patients, with a median activity of 16 µU/ml/hour (range 1–85 µU/ml/hour). The XO-activity was influenced by gender (male 19.5 vs. female 14.0 µU/ml/hour, p < 0.01), patient's age (Pearson's correlation r = 0.21, p = 0.02) and duration of IBD (r = 0.23, p = 0.01). The XO activity was not affected by the type of IBD, smoking status, body mass index or (type of) thiopurine use (p > 0.05).

Conclusions: There is a high inter-individual variability of XO-activity in IBD-patients; XO-activity is positively associated with male gender and patient's age.     

Cover Picture: Biotechnology Journal 2/2010

Cover illustration Focus: Transgenic Crops. This issue of BTJ highlights two articles about transgenic crops. Erlendsson et al. show for the first time that barley can be used as a green factory for growth factors (pp. 163–171); Herman et al. use a transclinic medicine model to access the safety of transgenic crops (pp. 172–182); Image © PhotoDisc/Getty Images. http://dx.doi.org/10.1002/biot.200900111 ; http://dx.doi.org/10.1002/biot.200900217 .     

Effects of exposure to electromagnetic field from mobile phone on serum hepcidin and iron status in male albino rats

Background: Electromagnetic fields (EMF) created by mobile phones during communication have harmful effects on different organs.

Objectives: To explore the effects of exposure to EMF of mobile phones for different durations on hematological parameters and serum hepcidin in male albino rats.

Methods: Three groups of eight rats: Sham group: rats were exposed to a mobile phone while it was switched off, Experimental group I: rats were exposed to microwave radiation from a mobile phone at 9 am for 30 min. Experimental group II: rats were exposed to microwave radiations from a mobile phone at 9 am for an hour. In all groups, the exposure was conducted daily for a total period of 5 months, followed by estimation of serum hepcidin, total leukocyte count (TLC), interleukin 6 (IL6), serum iron, serum ferritin, plasma hemoglobin (Hb), hematocrit value (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), unsaturated iron binding capacity (UIBC), total iron binding capacity (TIBC) and 1.25 dihydroxycholecalciferol levels.

Results: In Experimental group II, there was a significant increase in serum hepcidin, TLC, IL6 and serum ferritin; however, serum iron, TIBC, UIBC, 1.25 dihydroxycholecalciferol, plasma Hb, Hct, MCV and MCH were significantly lower in comparison to sham-exposed group. In Experimental group I, there was a significant increase in serum hepcidin, IL6 and TLC, along with non-significant changes in the remaining studied parameters in comparison to the sham-exposed group. Conclusion: Chronic exposure to EMF from mobile phones increases hepcidin level with subsequent impairment of iron parameters, in addition to negatively affecting both UIBC and TIBC.     

The clinical efficacy of angiotensin II type1 receptor blockers on inflammatory markers in patients with hypertension: a multicenter randomized-controlled trial; MUSCAT-3 study

Purpose: The purpose of present study was to evaluate the clinical efficacy of irbesartan on the anti-inflammatory and anti-oxidative stress effect in patients with hypertension compared to other ARBs. Further, we assessed the effect of the ARBs on kidney function and urinary albumin excretion.

Methods: Eighty-five outpatients with hypertension who took an ARB except irbesartan more than 3?months were assigned into two groups, one continued the same ARB and the other switched the ARB to irbesartan for 6?months.

Results: Although blood pressures were equally controlled (continue group: 148?±?2/79?±?2?mmHg to 131?±?2/74?±?2?mmHg; switch group: 152?±?2/81?±?2?mmHg to 132?±?2/74?±?2?mmHg; p?<?0.001 each), the inflammatory markers (hsCRP, PTX3, MCP-1) and oxidative stress marker (MDA-LDL) did not change after 6?months in both groups. Urinary albumin excretion was significantly reduced only in the switch group without renal function deterioration (switch group 292.4?±?857.9?mg/gCr to 250.6?±?906.5?mg/gCr, p?=?0.012).

Conclusion: These results provide knowledge of the characteristics of irbesartan, suggesting appropriate choice of ARBs in the treatment for hypertension should be considered.     

Bioprocess Scale-up/down

Cover illustration: Scale-up and scale-down strategies are a key for successful implementation of bioprocesses in industry. This issue of Biotechnology Journal, edited by Peter Neubauer (TU Berlin, Germany), features articles on methods for improved scale-up and -down strategies, e.g. measuring CO₂ gradients, drop breakage analysis and study of metabolic stress. One review article by Alvin Nienow presents strategies for improved beer production (http://dx.doi.org/10.1002/biot.201000414 ). Cover image: Outdoor fermentation vessels at a Spanish brewery. ©Olaf Hendel (Versuchs- und Lehranstalt für Brauerei in Berlin (VLB) e.V.).     

Early Neogene biochemostratigraphy of Pohang Basin: a paleoceanographic response to the early opening of the Sea of Japan (East Sea)

The location of the Pohang Basin near the Korea Strait in the southwest of the Sea of Japan (East Sea) makes this area appropriate for providing a record of paleoenvironmental/biotic changes associated with the early Neogene (16.5 Ma) opening of this gateway to the Pacific Ocean. Stable isotopic and planktonic foraminiferal records are presented that assist with the understanding of paleoenvironmental changes in the Sea of Japan resulting from the opening of the Korea Strait. The oldest sediments of early Neogene age of the Pohang Basin overlie Cretaceous basement and are Early Miocene (>16.5 Ma) shallow, estuarine facies containing a benthic foraminiferal assemblage dominated by Ammonia beccarii (L.). The oldest early Neogene planktonic foraminiferal assemblages in the basin are 16.5 Ma in age (latest Early Miocene foraminiferal zone N8). The migration of these planktonic assemblages to the Sea of Japan at that time appears to have resulted from the initial opening of the Korea Strait. The overlying early Neogene marine sequence of the Pohang Basin extends from 16.5 Ma (Zone N8) through 14 Ma (Zone N10). Change in the oxygen isotopic record of the Pohang Basin sequence suggests strong local paleoenvironmental control related to the early opening of the Korea Strait. Early Middle Miocene isotopic temperatures of planktonic foraminifera are relatively cool at 15 Ma at a time when global temperatures were high in the middle/low latitude regions. It was not until 14.8 Ma that isotopic temperatures of planktonic foraminifera increased markedly. This distinct warming is inferred to reflect the major intrusion of the Kuroshio Current into the Sea of Japan probably as a result of further critical opening and deepening of the Korea Strait. At this time planktonic foraminifera increased in abundance reflecting expanding oceanic influence. A cooling that followed at 14.5 Ma, when the strait was well open is unlikely to reflect local tectonic control on the paleoceanography, but global cooling during the early Middle Miocene associated with the expansion of the East Antarctic ice sheet.     

A clinical analysis on 40 cases of spontaneous intracranial hypotension syndrome

Objective: To investigate clinical and imaging features of 40 patients with spontaneous intracranial hypotension (SIH).

Methods: 40 cases of spontaneous intracranial hypotension (SIH) diagnosed in our hospital from June 2013 to September 2017 were collected and retrospectively analyzed.

Results: In our study, the male to female ratio was 2:3. The average age of onset was 43.0?±?15.0?years. There were 12 (30.0%) patients with clear incentives, mostly catching cold. The average length of hospital stay was 11.2?±?6.3?days. All the patients showed orthostatic headaches, 62.5% patients with nausea or vomiting, 40.0% patients with neck stiffness, 17.5% patients with dizziness and vertigo, 10.0% patients with numbness and weakness of limbs, 5% patients with neck discomfort, and 2.5% patients with visual symptoms (visual impairment, photophobia, diplopia). 24 patients underwent CT scans which showed no abnormalities in 20 cases (83.3%), subdural fluid accumulation in 3 cases (12.5%), and subdural haematoma in 1 case (2.5%). Cranial contrast-enhanced MR scans showed diffuse pachymeningeal enhancement (95.83%, 23/24), signs of pituitary hyperaemia in 5 cases (20.8%), subdural fluid accumulation and subdural hematoma in 4 cases (16.7%), sagging of the brain in 3 cases (12.5%), and engorgement of venous structures in 1 case (4.1%). Six patients underwent plain and contrast-enhanced spinal MR scans which showed varying degrees of dural thickening and enhanced performance in all the patients. 92.5% (37/40) of patients had cerebrospinal fluid pressure <60 mmH₂O on lumbar puncture. 97.5% of patients underwent conservative treatment with drugs and had a good outcome.

Conclusion: Orthostatic headache and cranial MRI diffuse pachymeningeal enhancement are characteristic features of SIH. Cranial contrast-enhanced MR scan is recognized as the first and non-invasive investigation in the diagnosis of SIH. Most patients had cerebrospinal fluid pressure <60 mmH₂O. The vast majority of patients improved with fluid replacement.     

Soluble ST2 is associated with disease severity in arrhythmogenic right ventricular cardiomyopathy

Purpose: Diagnostic and prognostic evaluation remains challenging in arrhythmogenic right ventricular cardiomyopathy (ARVC). We measured plasma concentration of soluble ST2 (sST2) and assessed its association with right ventricular (RV) function and ventricular arrhythmias in patients with ARVC.

Methods: We included patients with ARVC and genotype positive relatives. Soluble ST2 was determined by ELISA. We assessed myocardial function by echocardiography including strain by speckle tracking technique.

Results: We included 44 subjects (age 41?±?15 years, 21 (48%) female). Soluble ST2 was associated with RV global strain (r?=?0.44; p?=?0.008), as well as with left ventricular (LV) function. Plasma levels of sST2 were higher in patients with ventricular arrhythmias than in patients without ventricular arrhythmias (35?±?13?ng/mL vs. 26?±?7?ng/mL, p?=?0.009). The association between sST2 and ventricular arrhythmias remained significant even after adjusting for RV function (Wald?=?5.2; p?=?0.02).

Conclusions: Soluble ST2 is associated with RV and LV function in patients with ARVC. Soluble ST2 may aid in the determination of disease severity in ARVC.     

Relationship between myocardial bridge compression severity and haemodynamic perturbations

Objectives: This study aims to examine the alteration in coronary haemodynamics with increasing the severity of vessel compression caused by myocardial bridging (MB).

Methods: Angiography and intravascular ultrasound were performed in 10 patients with MB with varying severities of systolic compression in the left anterior descending (LAD) artery. Computer models of MB were developed and transient computational fluid dynamics simulations were performed to derive distribution of blood residence time and shear stress.

Results: With increasing the severity of bridge compression, a decreasing trend was observed in the shear stress over proximal segment whereas an increasing trend was found in the shear stress over bridge segment. When patients were divided into 2 groups based on the average systolic vessel compression in the whole cohort (%CR_ave = 27.38), patients with bridges with major systolic compression (>%CR_ave) had smaller shear stress and higher residence time in the proximal segment compared to those with bridges with minor systolic compression (<%CR_ave) (0.37?±?0.23 vs 0.69?±?0.29?Pa and 0.0037?±?0.0069 vs 0.022?±?0.0094?s). In contrast, patients with bridges with major systolic compression had greater shear stress in the bridge segment compared to those with bridges with minor systolic compression (2.49?±?2.06 vs 1.13?±?0.89?Pa). No significant difference was found in the distal shear stress of patients with bridges with major and minor systolic compression.

Conclusion: Our findings revealed a direct relationship between the severity of systolic compression of MB and haemodynamic perturbations in the proximal segment such that the increased systolic vessel compression was associated with decreased shear stress and increased blood residence time.     

Effects of night shift on the cognitive load of physicians and urinary steroid hormone profiles – a randomized crossover trial

Mental and physical stress is common in physicians during night shifts. Neurocognitive effects of sleep deprivation as well as alterations in hormonal and metabolic parameters have previously been described. The aim of this crossover study was to evaluate the effects of night-shift work with partial sleep deprivation on steroid hormone excretion and possible associations with mood, sleep characteristics and cognitive functions in physicians.

In total, 34 physicians (mean age 42 ± 8.5 years, 76.5% male) from different departments of the General Hospital of Vienna, Austria, were randomly assigned to two conditions: a regular day shift (8 h on duty, condition 1) and a continuous day-night shift (24 h on duty, condition 2). In both conditions, physicians collected a 24 h urine sample for steroid hormone concentration analysis and further completed psychological tests, including the sleep questionnaire (SF-A), the questionnaire for mental state (MDBF) and the computer-assisted visual memory test (FVW) before and at the end of their shifts, respectively.

Although mean sleep deprivation during night shift was relatively small (~1.5 h) the impairment in participants’ mental state was high in all three dimensions (mood, vigilance and agitation, p ≤ 0.001). Sleep quality (SQ), feeling of being recovered after sleep and mental balance decreased (p ≤ 0.001), whereas mental exhaustion increased (p < 0.05). Moreover, we could show a nearly linear relationship between most of these self-rating items. Testing visual memory participants made significantly more mistakes after night shift (p = 0.011), however, mostly in incorrectly identified items and not in correctly identified ones (FVW). SQ and false identified items were negatively correlated, whereas SQ and time of reaction were positively associated. It is assumed that after night shift, a tendency exists to make faster wrong decisions. SQ did not influence correctly identified items in FVW. In contrast to previous investigations, we found that only excretion rates for pregnanetriol and androsterone/etiocholanolone ratios (p < 0.05, respectively) were slightly reduced in 24-h urine samples after night shift. A considerable stimulation of the adrenocortical axis could not be affirmed. In general, dehydroepiandrosteron (DHEA) was negatively associated with the sense of recreation after sleep and with the time of reaction and positively correlated with correctly identified items in the FVW test.

These results, on the one hand, are in line with previous findings indicating that stress and sleep deprivation suppress gonadal steroids, but, on the other hand, do not imply significant adrenocortical-axis stimulation (e.g. an increase of cortisol) during the day-night shift.     

Persistence of social jetlag and sleep disruption in healthy young adults

Sleep disruption has been associated with increased risks for several major chronic diseases that develop over decades. Differences in sleep/wake timing between work and free days can result in the development of social jetlag (SJL), a chronic misalignment between a person’s preferred sleep/wake schedule and sleep/wake timing imposed by his/her work schedule. Only a few studies have examined the persistence of SJL or sleep disruption over time. This prospective investigation examined SJL and sleep characteristics over a 2-year period to evaluate whether SJL or poor sleep were chronic conditions during the study period. SJL and sleep measures (total sleep time [TST], sleep onset latency [SOL], wake after sleep onset [WASO]), and sleep efficiency [SE]), were derived from armband monitoring among 390 healthy men and women 21–35 years old. Participants wore the armband for periods of 4–10 days at 6-month intervals during the follow-up period (N = 1431 repeated observations).

The consistency of SJL or sleep disruption over time was analyzed using generalized linear mixed models (GLMMs) for repeated measures. Repeated measures latent class analysis (RMLCA) was then used to identify subgroups among the study participants with different sleep trajectories over time. Individuals in each latent group were compared using GLMMs to identify personal characteristics that differed among the latent groups.

Minor changes in mean SJL, chronotype, or TST were observed over time, whereas no statistically significant changes in SOL, WASO, or SE were observed during the study period. The RMLCA identified two groups of SJL that remained consistent throughout the study (low SJL, mean ± SE: 0.4 ± 0.04 h, 42% of the study population; and high SJL, 1.4 ± 0.03 h, 58%). Those in the SJL group with higher values tended to be employed and have an evening chronotype.

Similarly, two distinct subgroups were observed for SOL, WASO, and SE; one group with a pattern suggesting disrupted sleep over time, and another with a consistently normal sleep pattern. Analyses of TST identified three latent groups with relatively short (5.6 ± 1.0 h, 21%), intermediate (6.5 ± 1.0 h, 44%), and long (7.3 ± 1.0 h, 36%) sleep durations, all with temporally stable, linear trajectories. The results from this study suggest that sleep disturbances among young adults can persist over a 2 year period. Latent groups with poor sleep tended to be male, African American, lower income, and have an evening chronotype relative to those with more normal sleep characteristics. Characterizing the persistence of sleep disruption over time and its contributing factors could be important for understanding the role of poor sleep as a chronic disease risk factor.     

Anti-diabetic effect of S-adenosylmethionine and α-glycerophosphocholine in KK-Ay mice

Six-week-old male KK-A^y mice received drinking water with S-adenosylmethionine (SAM), α-glycerophosphocholine (GPC), or SAM+GPC for 10 weeks. The serum glucose of SAM+GPC at 15 weeks old, total cholesterol of GPC at 12 weeks old, and triglyceride of GPC at 15 weeks old and of SAM at 16 weeks old were reduced. SAM+GPC reduced serum leptin and food intake.

Abbreviations: SAM: S-adenosylmethionine; GPC: α-glycerophosphocholine     

Epidemiology of objectively measured bedtime and chronotype in US adolescents and adults: NHANES 2003–2006

Background: We propose a method for estimating the timing of in-bed intervals using objective data in a large representative US sample, and quantify the association between these intervals and age, sex, and day of the week.

Methods: The study included 11,951 participants 6 years and older from the National Health and Nutrition Examination Survey (NHANES) 2003–2006, who wore accelerometers to measure physical activity for seven consecutive days. Participants were instructed to remove the device just before the nighttime sleep period and put it back on immediately after. This nighttime period of non-wear was defined in this paper as the objective bedtime (OBT), an objectively estimated record of the in-bed interval. For each night of the week, we estimated two measures: the duration of the OBT (OBT-D) and, as a measure of the chronotype, the midpoint of the OBT (OBT-M). We estimated day-of-the-week-specific OBT-D and OBT-M using gender-specific population percentile curves. Differences in OBT-M (chronotype) and OBT-D (the amount of time spent in bed) by age and sex were estimated using regression models.

Results: The estimates of OBT-M and their differences among age groups were consistent with the estimates of chronotype obtained via self-report in European populations. The average OBT-M varied significantly by age, while OBT-D was less variable with age. In the reference group (females, aged 17–22 years), the average OBT-M across 7 days was 4:19 AM (SD = 30 min) and the average OBT-D was 9 h 19 min (SD = 12 min). In the same age group the average OBT-D was 18 minutes shorter for males than for females, while the average OBT-M was not significantly different between males and females. The most pronounced differences were observed between OBT-M of weekday and weekend nights. In the reference group, compared to the average OBT-M of 3:50 am on Monday through Thursday nights, there was a 57-minute delay in OBT-M on Friday nights (entering the weekend), a 69-minute delay on Saturday nights (staying in the weekend), and a 23-minute delay on Sunday night (leaving the weekend). For both OBT-M and OBT-D, in most age groups and for most days of the week, there were no statistically significant differences between males and females, except for OBT-D on Wednesdays and Thursdays, with males having 31 (p-value < 0.05) and 45 (p-value < 0.05) minutes shorter OBT-D, respectively.

Conclusions: The proposed measures, OBT-D and OBT-M, provide useful information of time in bed and chronotype in NHANES 2003–2006. They identify within-week patterns of bedtime and can be used to study associations between the bedtime and the large number of health outcomes collected in NHANES 2003–2006.     

The first Tanyderidae (Diptera) from Lower Cretaceous Álava amber (Spain)

A new genus and species, Espanoderus barbarae gen. et sp. nov., belonging to the family Tanyderidae (Diptera, Nematocera), is described from Lower Cretaceous amber of Spain (Álava amber). The new genus is the smallest member of Tanyderinae and the first member of the family from the Álava amber. The position of the new genus in a phylogenetic tree of Tanyderidae is presented.

http://zoobank.org/urn:lsid:zoobank.org:pub:EC3284BA-C07F-48AC-8AF5-4F9D2EF4EA6C