Effects of sleep fragmentation and partial sleep restriction on heart rate variability during night

We developed a cross-over study design with two interventions in randomized order to compare the effects of sleep fragmentation and partial sleep restriction on cardiac autonomic tone. Twenty male subjects (40.6 ± 7.5 years old) underwent overnight polysomnography during 2 weeks, each week containing one undisturbed baseline night, one intervention night (either sleep restriction with 5 h of sleep or sleep fragmentation with awakening every hour) and two undisturbed recovery nights. Parameters of heart rate variability (HRV) were used to assess cardiac autonomic modulation during the nights. Sleep restriction showed significant higher heart rate (p = 0.018) and lower HRV-pNN50 (p = 0.012) during sleep stage N1 and lower HRV-SDNN (p = 0.009) during wakefulness compared to the respective baseline. For HR and SDNN there were recovery effects. There was no significant difference comparing fragmentation night and its baseline. Comparing both intervention nights, sleep restriction had lower HRV high frequency (HF) components in stage N1 (p = 0.018) and stage N2 (p = 0.012), lower HRV low frequency (LF) (p = 0.007) regarding the entire night and lower SDNN (p = 0.033) during WASO during sleep. Sleep restriction increases sympathetic tone and decreases vagal tone during night causing increased autonomic stress, while fragmented sleep does not affect cardiac autonomic parameters in our sample.

Schlafqualität und kardialer autonomer Tonus bei Leistungssporttreibenden und in einer Referenzgruppe Gesunder

Leistungssportlerinnen und Leistungssportler sind hohen physischen und psychischen Anforderungen ausgesetzt, um optimale Ergebnisse zu erzielen. Dafür ist auch die Funktion der Regenerationsphase wichtig, zu der maßgeblich ein erholsamer Schlaf beiträgt. Es gibt jedoch Hinweise, dass bei Leistungssportlerinnen und Leistungssportlern aufgrund verschiedener Belastungen im Rahmen des Trainings und der Wettkämpfe gehäuft eine Insomniesymptomatik auftreten kann. Zur objektiven Untersuchung der Schlafstruktur, Schlafqualität und Funktion des kardialen autonomen Tonus wurden Leistungssporttreibende (LS) und eine Gruppe ebenfalls gesunder Kontrollen (GK) mit einer vereinfachten ambulanten Schlafmessung untersucht.

Es wurde in der Gruppe LS bei n = 12 Probanden (Alter 25,1 ± 4,3 Jahre) und in der Gruppe GK bei n = 17 Probanden (Alter 26,1 ± 3,2 Jahre) jeweils weiblichen und männlichen Geschlechts erfolgreich im häuslichen Umfeld eine vereinfachte Schlafmessung einschließlich 1‑Kanal-EKG (SOMNOtouch™) durchgeführt. Mittels Fragebögen wurden die Tagesschläfrigkeit (Epworth Sleepiness Scale, ESS), Insomnieschwere (Insomnia Severity Index, ISI) und Symptome für Schlafapnoe (Aktualisierter STOP-Bang-Fragebogen, aSBF) erhoben. Es wurden visuell die Schlafstadien gescort und aus dem EKG mittels Zeitreihenanalyse Parameter der Herzfrequenz und Herzfrequenzvariabilität (HRV) ausgewertet.

Es traten keine Unterschiede zwischen den Gruppen LS und GK hinsichtlich der ESS und aSBF auf, jedoch war die ISI in der Gruppe LS gegenüber GK erhöht (5,7 ± 4,1 vs. 2,4 ± 2,0; p < 0,02). In Auswertung der Schlafstruktur gab es keine Unterschiede für die Einschlaflatenz (ESL), Gesamtschlafzeit (TST), Schlafeffizienz (SE) sowie für die prozentualen Anteile von Leicht- (N1 + N2), Tief- (N3) und REM-Schlaf (REM), jedoch war die Bettzeit (TIB) in der Gruppe LS erhöht (503,2 ± 52,7 vs. 445,5 ± 45,4 min; p < 0,02). In der Gruppe LS waren gegenüber der Gruppe GK die mittlere nächtliche Herzfrequenz verringert (48,5 ± 6,8 vs. 56,1 ± 5,4; p < 0,01) sowie die HRV-Parameter HRV-Standardabweichung (HRV-SD) (166,0 ± 33,2 vs. 138,2 ± 38,7; p < 0,04), HRV-SD1 (78,8 ± 11,7 vs. 63,2 ± 36,5; p < 0,01) und HRV-SD2 (220,6 ± 48,0 vs. 183,8 ± 45,8; p < 0,05) erhöht.

In der von uns untersuchte Gruppe von Leistungssportlerinnen und Leistungssportlern gibt es Anhaltspunkte für eine leichte Insomnie, wobei die objektiv gemessene Schlafstruktur sich nicht von der gesunder Kontrollen unterscheidet. Dabei ist die TST, mit einem Mittelwert von 6,8 h sowohl in der Gruppe LS als auch in GK, geringer als die von den Fachgesellschaften American Academy of Sleep Medicine (AASM), Sleep Research Society (SRS) und National Sleep Foundation (NSF) empfohlene Schlafdauer für junge Erwachsene. Dagegen war die kardiale autonome Regulation im Schlaf in der Gruppe LS signifikant besser als in der Gruppe GK und ist in Übereinstimmung mit Befunden aus 24-Stunden-Holter-EKG-Studien. Die Entwicklung objektiver, mobiler und belastungsarmer Messverfahren vereinfacht die Erfassung der Schlafstruktur und charakteristischer vegetativer Parameter und könnte zunehmend im personalisierten Gesundheits- und Leistungsmanagement bei Leistungssporttreibenden eingesetzt werden.

Effect of the new dual orexin receptor antagonist daridorexant on nighttime respiratory function and sleep in patients with mild and moderate obstructive sleep apnea

In this randomized, double-blind, placebo-controlled, two-period crossover study, the effect of the dual orexin receptor antagonist daridorexant was evaluated on nighttime respiratory function and sleep in 28 patients with mild and moderate obstructive sleep apnea (OSA). In each period, 50 mg daridorexant or placebo was administered every evening for 5 days. The primary endpoint was apnea/hypopnea index (AHI) during total sleep time (TST) after the last dosing. Other endpoints included peripheral oxygen saturation (SpO2), sleep duration, latency to persistent sleep (LPS), wake after sleep onset (WASO), and sleep efficiency index (SEI). Pharmacokinetics, safety, and tolerability were also assessed. The mean treatment difference for AHI during TST (i.e. daridorexant - placebo) after the last dosing was 0.74 events/hour (90% confidence interval [CI]: -1.43, 2.92). The corresponding treatment difference for SpO2 during TST was 0.16% [90% CI: -0.21, 0.53]. Overall, there was no clinically relevant effect of daridorexant on AHI or SpO2-related data after single and repeated dosing irrespective of sleep phase (i.e. rapid eye movement [REM] vs non-REM). Moreover, after single and repeated dosing, daridorexant prolonged TST by 39.6 minutes (90% CI: 16.9, 62.3) and 38.8 minutes (19.7, 57.9), respectively, compared with placebo and favorably modulated other sleep-related endpoints (i.e. increased SEI, decreased WASO, and shortened LPS). It attained expected plasma concentrations and was well tolerated in patients with mild and moderate OSA. These results indicate that single and repeated doses of 50 mg daridorexant do not impair nighttime respiratory function and improve sleep in patients with mild and moderate OSA. Clinical Trial Registration: ClinicalTrials.gov NCT03765294. A study to investigate the effects of ACT-541468 on nighttime respiratory function in patients with mild to moderate obstructive sleep apnea. https://clinicaltrials.gov/ct2/show/ NCT03765294.

357 Daridorexant Does Not Impair Respiratory Function in Patients with Mild/Moderate Obstructive Sleep Apnea Irrespective of Severity

Introduction

Daridorexant is a dual orexin receptor antagonist developed for the treatment of insomnia. The effect of the highest phase-3 dose of 50 mg daridorexant on nighttime respiratory function was evaluated in patients with mild/moderate obstructive sleep apnea (OSA). This study showed that repeated doses of daridorexant had no clinically meaningful effect on nighttime respiration (i.e., apnea-hypopnea index [AHI] and peripheral oxygen saturation [SpO2]). In the same study, other relevant respiratory endpoints were evaluated.

Methods

In this randomized, double-blind, placebo-controlled, two-period, crossover study, daridorexant or placebo was administered in each period once daily for 5 consecutive nights to 28 patients. Treatment differences (daridorexant – placebo) for total number and mean/longest duration of apneas and hypopneas as well as mean and lowest SpO2 during apnea/hypopnea events in Night 5 were explored using linear mixed-effects modeling. Treatment differences for the above-mentioned endpoints versus AHI during TST at baseline (i.e., OSA severity) was analyzed by linear regression using least square approach.

Results

Of 28 patients enrolled, 25 completed the study and were included in the analysis (n=15/10 with mild/moderate OSA; mean [standard deviation, SD] AHI: 16.3 events/h [8.2]). Compared to placebo, daridorexant increased mean duration of TST and accordingly to a not statistically significant extent the mean number of apneas + hypopneas by 16.4 events (n=103 versus 86.2; 90% confidence interval [CI]: -0.4–33.2]) without difference in mean [SD] AHI between daridorexant (15.1 events/h [7.9] and placebo (14.2 [7.7]). No treatment difference was detected for mean (0.0 sec [-2.6–2.7]) or longest (0.8 sec [-8.9–10.5]) duration of apneas nor for mean (0.2 sec [-2.2–2.5]) or longest (8.3 sec [6.4–23.1]) duration of hypopneas. No treatment difference was observed for mean (0.3% [-0.2–2.1]) and lowest (0.9% [0.3–2.1]) SpO2 during apnea/hypopnea events. Treatment differences for any of the evaluated endpoints did not significantly correlate with AHI at baseline as a marker of OSA severity (r2 ≤ 0.09).

Conclusion

Daridorexant can safely be administered to patients with mild/moderate OSA as treatment differences for respiratory-related endpoints were not of statistical significance and independent of disease severity in the studied population.

Support (if any)

Funded by Idorsia Pharmaceuticals Ltd.

358 Daridorexant Improves Sleep in Patients with Mild/Moderate Obstructive Sleep Apnea

Introduction

Daridorexant is a dual orexin receptor antagonist developed for the treatment of insomnia. The effect of the highest phase-3 dose of 50 mg daridorexant on nighttime respiratory function was evaluated in patients with mild/moderate obstructive sleep apnea (OSA). This study showed that repeated doses of daridorexant had no clinically meaningful effect on the apnea-hypopnea index (AHI) or on peripheral oxygen saturation. In the same study, the effect on objective sleep parameters was also explored by polysomnography (PSG).

Methods

In this randomized, double-blind, placebo-controlled, two-period, crossover study, daridorexant or placebo was administered in each period once daily for 5 consecutive nights to 28 patients. Treatment difference (daridorexant – placebo) for total sleep time (TST), latency to persistent sleep (LPS), and wake after sleep onset (WASO) was analyzed for Night 5 using linear mixed-effects modeling. In addition, sleep was further explored based on sleep duration during each hour of PSG recording, duration of the different sleep phases (rapid eye movement [REM], non-REM [including N1 to N3 sleep stages]), as well as number and mean/longest duration of awakenings.

Results

Of 28 patients enrolled, 25 completed the study and were included in the analysis (n=15/10 with mild/moderate OSA; mean [standard deviation] AHI: 16.3 [8.2] events/h). One patient had mild insomnia symptoms at baseline. Compared to placebo, daridorexant prolonged mean TST by 38.8 min (90% confidence interval: 19.7–57.9), shortened mean LPS by 17.2 min (-35.5–1.02), and reduced mean WASO by 31.0 min (-47.3 to 14.7). Sleep architecture was maintained as no treatment differences in the duration of the evaluated sleep stages were observed when normalized to TST. Sleep duration was prolonged in the second part of the night. mean and longest duration of awakenings were decreased by a mean (90% CI) of 2.0 min (-3.1 to 0.9) and 16.3 min (-24.1 to -8.6), respectively, without treatment difference for the total number of awakenings.

Conclusion

Daridorexant improved objective sleep parameters in patients with mild to moderate OSA without modifying sleep architecture.

Support (if any)

Funded by Idorsia Pharmaceuticals Ltd.

Effect of the novel dual orexin receptor antagonist daridorexant on night-time respiratory function and sleep in patients with moderate chronic obstructive pulmonary disease

In patients with chronic obstructive pulmonary disease (COPD), sleep is often fragmented while, conversely, the use of sleep medications is of concern in these patients due to potential impairment of nocturnal breathing. This randomised, double-blind, placebo-controlled, two-period crossover study was conducted to evaluate the effect of the new dual orexin receptor antagonist daridorexant on night-time respiratory function and sleep in patients with moderate COPD. In each period, the highest Phase-III dose of 50 mg daridorexant or placebo was administered once daily in the evening for 5 consecutive days. The primary endpoint was peripheral oxygen saturation (SpO₂ ) during total sleep time (TST) after last dosing. Night-time respiratory function and sleep were further evaluated based on the apnea-hypopnea index (AHI), sleep duration, and objective sleep parameters. Pharmacokinetics, safety, and tolerability were also assessed. Primary endpoint analysis revealed no significant mean treatment difference (i.e. daridorexant - placebo) for SpO₂ during TST as it was 0.18% (90% confidence interval: -0.21 to 0.57). There was also no difference from placebo for SpO₂ during non-rapid eye movement (REM) and REM sleep at Night 5 and after first dosing. The AHI was slightly increased compared to placebo, but not to a clinically meaningful extent. In addition, daridorexant improved objective sleep parameters (i.e. prolonged TST, increased sleep efficiency, and decreased wake after sleep onset), reached expected plasma concentrations, and was safe and well tolerated. In conclusion, single and multiple doses of 50 mg daridorexant do not impair night-time respiratory function and improves sleep in patients with moderate COPD.

Screening for obstructive sleep apnea with novel hybrid acoustic smartphone app technology

Background

Obstructive sleep apnea (OSA) has a high prevalence, with an estimated 425 million adults with apnea hypopnea index (AHI) of ≥15 events/hour, and is significantly underdiagnosed. This presents a significant pain point for both the sufferers, and for healthcare systems, particularly in a post COVID-19 pandemic world. As such, it presents an opportunity for new technologies that can enable screening in both developing and developed countries. In this work, the performance of a non-contact OSA screener App that can run on both Apple and Android smartphones is presented.

Methods

The subtle breathing patterns of a person in bed can be measured via a smartphone using the "Firefly" app technology platform [and underpinning software development kit (SDK)], which utilizes advanced digital signal processing (DSP) technology and artificial intelligence (AI) algorithms to identify detailed sleep stages, respiration rate, snoring, and OSA patterns. The smartphone is simply placed adjacent to the subject, such as on a bedside table, night stand or shelf, during the sleep session. The system was trained on a set of 128 overnights recorded at a sleep laboratory, where volunteers underwent simultaneous full polysomnography (PSG), and "Firefly" smartphone app analysis. A separate independent test set of 120 recordings was collected across a range of Apple iOS and Android smartphones, and withheld for performance evaluation by a different team. An operating point tuned for mid-sensitivity (i.e., balancing sensitivity and specificity) was chosen for the screener.

Results

The performance on the test set is comparable to ambulatory OSA screeners, and other smartphone screening apps, with a sensitivity of 88.3% and specificity of 80.0% [with receiver operating characteristic (ROC) area under the curve (AUC) of 0.92], for a clinical threshold for the AHI of ≥15 events/hour of detected sleep time.

Conclusions

The "Firefly" app based sensing technology offers the potential to significantly lower the barrier of entry to OSA screening, as no hardware (other than the user's personal smartphone) is required. Additionally, multi-night analysis is possible in the home environment, without requiring the wearing of a portable PSG or other home sleep test (HST).

Overnight pulse wave analysis to assess autonomic changes during sleep in insomnia patients and healthy sleepers

Insomnia has been associated with increased cardiovascular (CV) risk, which may be linked to sympathetic activation. Non-invasive overnight pulse wave analysis may be a useful tool to detect early signs of autonomic changes during sleep in insomniacs. Fifty-two participants (26 men, 37±13 years, BMI: 24±5 kg/m², 26 insomniacs/ 26 controls) underwent overnight polysomnography with pulse oximetry and pulse wave analysis including pulse rate, vascular stiffness (pulse propagation time, PPT), and a composite cardiac risk index based on autonomic function and overnight hypoxia. We identified two subgroups of insomniacs, with and without objectively disturbed sleep (sleep efficiency SE≤80%, n = 14 vs. SE>80%, n = 12), and observed increased pulse rate and vascular stiffness in insomnia cases when diagnosis was based on both, subjective and objective criteria. Both insomnia groups were associated with higher overnight pulse rate than controls (median/ IQR: low-SE (low sleep efficiency): 67/ 58-70bpm; high-SE: 66/ 63-69bpm; controls: 58/ 52-63bpm; p = 0.01). Vascular stiffness was higher (reduction of PPT) in low-SE insomniacs compared with high-SE insomniacs and controls (169/ 147-232ms; 237/ 215-254ms; 244/ 180-284ms; p = 0.01). The cardiac risk index was increased in low-SE insomniacs (0.2/ 0.0–0.7; 0.0/ 0.0–0.4; 0.0/ 0.0–0.3; p = 0.05). Our results suggest a hyperarousal state in young and otherwise healthy insomniacs during sleep. The increased pulse rate and vascular stiffness in insomniacs with low SE suggest early signs of rigid vessels and potentially, an elevated CV risk. Overnight pulse wave analysis may be feasible for CV risk assessment in insomniacs and may provide a useful tool for phenotyping insomnia in order to provide individualized therapy.

Sleep Staging Monitoring Based on Sonar Smartphone Technology

This paper presents the validation results of a new non-contact ultrasonic technology, which employs inaudible Sonar to monitor the movements and respiration of a subject in bed. Sleep monitoring can be achieved by placing a smartphone onto the bedside table and starting a custom app. The app employs sophisticated and novel proprietary algorithms to identify sleep stages: Wake (W), Light Sleep (N1, N2 sleep), Deep Sleep (N3 sleep), Rapid Eye Movement (REM) Sleep or Absence.The sleep staging performance of the app were assessed by testing it against expert manually scored polysomnography (PSG) of 38 subjects gathered in a sleep laboratory. As a secondary assessment, on the same dataset, the performance of the app is compared to that of a reference non-contact device, the S+ by ResMed.Performance across different sleep stage detections was balanced, exceeding the agreement typically reported for actigraphy based devices [1], [2] thanks to a significantly higher sensitivity for all sleep stages. Furthermore, the performance of the app was found to be comparable to the S+ by ResMed product [3], [4].The combination of unobtrusive non-contact sensing and accurate sleep quality assessment, coupled with removal of the requirement to purchase a custom device to enable monitoring of sleep, enables consumers to measure their sleep in the home environment in a zero-cost and accessible manner, while providing sleep staging information not otherwise available with actigraphy based devices.

Ein optimierter Versorgungsprozess bei Patienten mit schlafbezogenen Atmungsstörungen – Pilotstudie

Hintergrund

Die Einweisung der Patienten in die diagnostische Polygraphie wird bisher von einer medizinisch ausgebildeten Fachkraft durchgeführt. Dieser Prozess ist zeit- und ressourcenintensiv. In dieser Pilotstudie wurde ein innovativer Versorgungsweg bei schlafbezogenen Atmungsstörungen (SBAS) untersucht, um eine beschleunigte Diagnostik und effektivere Therapiezuweisung zu erreichen. Hierfür wurde den Studienteilnehmern ein Polygrafie (PG)-Gerät direkt von der versorgenden Firma nach Hause geliefert.

Methodik

Der Patient legte die PG selbstständig nach einer Bedienungsanleitung an und erhielt bei Bedarf telefonische Unterstützung. Nach der Untersuchungsnacht wurde das Gerät zurückgesendet. Die ärztliche Befundung erfolgte online über ein verschlüsseltes Portal. Zusätzlich erfolgte eine Befragung zur subjektiven Zufriedenheit mit dem Ablaufprozess sowie ein Vergleich der PG-Ergebnisse mit einer zeitnahen Polysomnografie (PSG).

Ergebnisse

Es wurden 50 Patienten (m = 30/w = 20) mit Verdacht auf SBAS im mittleren Alter von 50,5 ± 13,7 Jahren eingeschlossen. Die Probanden wiesen unter beiden Messverfahren einen ähnlichen mittleren Apnoe-Hypopnoe-Index (AHI) (PSG) von M = 20,8 (SD 23,2) und AHI (PG) von M = 20,2 (SD 18,9) auf. Bei AHI-Werten zwischen ≥15–<30/h ergab sich eine Sensitivität von 63 % und Spezifität von 88 % für die PG im Vergleich zur PSG. Bei AHI-Werten >30/h lag die Sensitivität bei 88 % und die Spezifität bei 91 %.

Diskussion

In der Beurteilung, ob eine klinisch relevante Schlafapnoe vorliegt, zeigte sich eine eher schwache, moderate Übereinstimmung zwischen den einzelnen Diagnosekategorien der Messverfahren, wobei sich die häufigsten Übereinstimmungen in den höchsten und niedrigsten Diagnosegruppen zeigten. Die Ergebnisse lassen jedoch aufgrund der selektiven Stichprobe keine Prognosen hinsichtlich der Durchführbarkeit in einer allgemeinen oder multimorbiden Patientengruppe zu.

A sleep intervention study comparing effects of sleep restriction and fragmentation on sleep and vigilance and the need for recovery

PURPOSE

Sleep deprivation is present not only in sleep disorders but also in numerous high demanding jobs and negatively affects cognition, performance and health. We developed a study design to distinguish the effects and need for recovery of two short-term disturbances - intermittent sleep fragmentation and partial sleep restriction.

METHODS

The randomized within-subjects design contained two weeks each with a baseline night, an intervention night of either sleep deprivation (5 h) or sleep fragmentation (light on every hour) and two undisturbed recovery nights. Twenty healthy male participants (mean age: 39.9 ± 7.4 years, mean BMI: 25.5 ± 2.2 kg/m²) underwent polysomnography, a psychomotor vigilance task (PVT), and subjective questions on well-being and sleep efficiency.

RESULTS

Percentage-wise, the restriction night had significant less wake times, less light sleep (stage 1), less REM sleep, but more deep sleep (stage 3) than the fragmentation night. The restriction week displayed a significant recovery effect regarding these sleep stages. The sleep fragmentation week presented a significant recovery effect regarding sleep onset times. PVT performance showed only a slight recovery effect after sleep restriction. Subjective sleep quality was reduced after both interventions with a significant recovery effect during restriction week only.

CONCLUSIONS

Short-term sleep restriction presented as a stronger sleep disturbance than short-term intermittent sleep fragmentation, including a stronger need for recovery. Already a one night sleep deprivation had an effect beyond two recovery days. The PVT was not sensitive enough to reveal significant changes. Next, autonomic parameters as possible biomarkers will be investigated.

Detection of Sleep Apnea Using Sonar Smartphone Technology

This paper assesses the performance of a new noncontact sensing system based on Sonar technology as a Sleep Disordered Breathing (SDB) screener. The respiration and movements of a subject in bed can be measured via a smartphone placed onto a bedside table equipped with a custom app. The app employs novel proprietary algorithms to identify sleep stages and detect SDB patterns.The SDB screener was trained on a set of 94 overnights recorded at a sleep laboratory, where volunteers underwent simultaneous monitoring via a full polysomnography (PSG) system and a smartphone equipped with the app. An additional fully independent set of 68 recordings, uniformly distributed across SDB severity classes, were held out for independent testing. The performance on the test set is excellent and comparable to other existing ambulatory SDB screeners, with a sensitivity of 94% and specificity of 97%, for a clinical threshold for the Apnea Hypopnea Index (AHI) of 15 events/hour.The technology can easily be adopted to scale, as no purchase of dedicated sensors is needed, providing a much needed low- cost alternative for monitoring and potentially screening of large population segments. Furthermore, the non-invasive, contactless sensing does not interfere with the sleeping habits of the user, facilitating longitudinal assessment. This, in combination with the simultaneous measurement of the user's sleep quality, could provide invaluable insights in the subject's response to SDB therapy and lead to increased patient adherence.

Effects of sleep on a high-heat capacity mattress on sleep stages, EEG power spectra, cardiac interbeat intervals and body temperatures in healthy middle-aged men‡

Study Objectives

This study deals with the question whether a slow (non-disturbing) reduction of core body temperature (CBT) during sleep increases sleep stage N3 and EEG slow wave energy (SWE) and leads to a slowing of heart rate in humans.

Participants

Thirty-two healthy male subjects with a mean ± SD age 46 ± 4 years and body mass index 25.2 ± 1.8 kg/m2.

Methods

A high-heat capacity mattress (HM) was used to lower body temperatures in sleep and was compared to a conventional low-heat capacity mattress (LM) in a double-blinded fashion. Polysomnography was performed accompanied by measurements of skin-, core body- and mattress surface-temperatures, and heart rate. EEG power spectral analyses were carried out using Fast Fourier Transform. Interbeat intervals were derived from the electrocardiogram.

Results

The HM led to a larger decline in CBT, mediated through higher heat conduction from the core via the proximal back skin onto the mattress together with reduced heart rate. These effects occurred together with a significant increase in sleep stage N3 and standardized slow wave energy (sSWE, 0.791–4.297 Hz) accumulated in NREM sleep. In the 2nd half of the night sSWE increase was significantly correlated with body temperature changes, for example with CBT decline in the same phase.

Conclusions

A HM subtly decreases CBT, leading to an increased amount of sleep stage N3 and of sSWE, as well as a slowing of heart rate.

White matter microstructure and impulsivity in methamphetamine dependence with and without a history of psychosis

BACKGROUND

Methamphetamine (MA) use may lead to white matter injury and to a range of behavioral problems and psychiatric disorders, including psychosis. The present study sought to assess white matter microstructural impairment as well as impulsive behavior in MA dependence and MA-associated psychosis (MAP).

METHODS

Thirty patients with a history of MAP, 39 participants with MA dependence and 40 healthy controls underwent diffusion tensor imaging (DTI). Participants also completed the UPPS-P impulsive behavior questionnaire. We applied tract-based spatial statistics (TBSS) to investigate group differences in mean diffusivity (MD), fractional anisotropy (FA), axial (λ‖ ) and radial diffusivity (λ⊥ ), and their association with impulsivity scores and psychotic symptoms.

RESULTS

The MAP group displayed widespread higher MD, λ‖ and λ⊥ levels compared to both controls and the MA group, and lower FA in extensive white matter areas relative to controls. MD levels correlated positively with negative psychotic symptoms in MAP. No significant DTI group differences were found between the MA group and controls. Both clinical groups showed high levels of impulsivity, and this dysfunction was associated with DTI measures in frontal white matter tracts.

CONCLUSIONS

MAP patients show distinct patterns of impaired white matter integrity of global nature relative to controls and the MA group. Future work to investigate the precise nature and timing of alterations in MAP is needed. The results are further suggestive of frontal white matter pathology playing a role in impulsivity in MA dependence and MAP. Hum Brain Mapp 37:2055-2067, 2016. © 2016 Wiley Periodicals, Inc.

Frontal white matter changes and aggression in methamphetamine dependence

Chronic methamphetamine (MA) use can lead to white matter (WM) changes and increased levels of aggression. While previous studies have examined WM abnormalities relating to cognitive impairment, associations between WM integrity and aggression in MA dependence remain unclear. Diffusion Tensor Imaging (DTI) was used to investigate WM changes in 40 individuals with MA dependence and 40 matched healthy controls. A region of interest (ROI) approach using tract based spatial statistics (TBSS) in FSL was performed. We compared fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (λ║) and perpendicular diffusivity (λ┴) in WM tracts of the frontal brain. A relationship of WM with aggression scores from the Buss & Perry Questionnaire was investigated. Mean scores for anger (p < 0.001), physical aggression (p = 0.032) and total aggression (p = 0.021) were significantly higher in the MA group relative to controls. ROI analysis showed increased MD (U = 439.5, p = 0.001) and λ┴ (U = 561.5, p = 0.021) values in the genu of the corpus callosum, and increased MD (U = 541.5, p = 0.012) values in the right cingulum in MA dependence. None of the WM changes were significantly associated with aggression scores. This study provides evidence of frontal WM changes and increased levels of aggression in individuals with MA dependence. The lack of significant associations between WM and aggressive behaviour may reflect methodological issues in measuring such behaviour, or may indicate that the neurobiology of aggression is not simply correlated with WM damage but is more complex.

Animal experiments with ultra-high molecular weight polyethylene (UHMW-PE) stabilised with alpha-tocopherol used for articulating surfaces in joint endoprostheses

Numerous investigations proved the impressive suitability of alpha-tocopherol as a stabilizer for ultra-high molecular weight polyethylene (UHMW-PE) used for endoprostheses. Regarding the biocompatibility of this new biomaterial, in-vitro celltoxicity tests gave no hint for a cyto- or genotoxic activity. In this study, animal experiments are carried out to further ensure the biocompatibility of this biomaterial. Thin UHMW-PE-films (20 x 6 x 0.23 mm3) were implanted subcutaneously into rats. Morphology and reactivity of surrounding connective tissue against either pure UHMW-PE material or UHMW-PE containing alpha-tocopherol were studied at timed intervals (2 weeks, 3 month, and 6 month after operation) in 3 groups of animals, each group comprising 10 animals. Parallel to these tests, material changes were investigated in these 3 groups of 10 animals at the same intervals after operation with the help of infrared spectroscopy (FTIR). Within the implantation time, no noteworthy oxidative degradation could be observed. The amount of lost alpha-tocopherol due to diffusion is low enough to ensure a lifetime stabilisation of the UHMW-PE. The implants were all well tolerated and definitely encapsulated already 2 weeks after operation. Presence or absence of alpha-tocopherol in the implants did not evince morphological differences. Therefore, negative consequences were not manifest in the presence of alpha-tocopherol.

Accelerated ageing experiments with crosslinked and conventional ultra-high molecular weight polyethylene (UHMW-PE) stabilised with alpha-tocopherol for total joint arthroplasty

Samples of untreated ultra-high molecular weight polyethylene (UHMW-PE), UHMW-PE sterilized with gamma-rays in nitrogen atmosphere (conventional UHMW-PE, widely used for articulating surfaces in endoprostheses) and UHMW-PE, which has been crosslinked by electron beam irradiation and annealed subsequently, were stabilized with alpha-tocopherol and aged in air at 120 degrees C as well as in 10% aqueous hydrogenperoxide with 0.04 mg/ml FeCl3 as catalyst at 50 degrees C. The oxidative degradation was monitored with the help of infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), solubility measurements and size exclusion chromatography (SEC) and were compared to unstabilized samples. When aged in air at 120 degrees C, the crosslinked UHMW-PE showed a slightly slower increase of the carbonyl (CO)-number (according to DIN 53383) in FTIR than conventional UHMW-PE. A stabilisation with 0.4% w/w alpha-tocopherol resulted in an increase of lifetime by a factor of approx. 40 for all samples. Ageing in 10% aqueous H2O2 at 50 degrees C yielded similar results for all three unstabilised samples. The addition of the natural antioxidant alpha-tocopherol led to a prolongation of lifetime by a factor of approx. 2.5. A linear loss of alpha-tocopherol was detected during ageing. An increase of crystallinity as well as lamella thickness during ageing was observed with the help of DSC. The two-phase structure of crosslinked UHMW-PE with two melting endotherms at 114 degrees C and 137 degrees C was replaced very quickly by a single melting point at 130 degrees C. This effect was delayed with the stabilized samples. In the solubility and SEC measurements, a severe molecular degradation and drop of molar mass of all materials could be observed after ageing in H2O2, leading to a complete destruction and, in case of crosslinked UHMW-PE, to a serious damage of the molecular network, respectively.

Stabilisation of crosslinked ultra-high molecular weight polyethylene (UHMW-PE)-acetabular components with alpha-tocopherol

A stabilisation of crosslinked ultra-high molecular weight polyethylene (UHMW-PE) with alpha-tocopherol (vitamin E) used for endoprostheses can increase its resistance against oxidative degradation remarkably. However, the method used for conventional UHMW-PE of adding alpha-tocopherol to the UHMW-PE powder before processing can not be applied for crosslinked UHMW-PE, since the alpha-tocopherol hinders the crosslinking process, which would be accompanied by a heavy degradation of this vitamin. The alpha-tocopherol has therefore to be added after the crosslinking process. This paper presents two methods for a stabilisation of finished products with alpha-tocopherol. In method 1, UHMW-PE-cubes (20 x 20 x 20 mm3) were stored in pure alpha-tocopherol under inert atmosphere at temperatures from 100 degrees C to 150 degrees C resulting in a high mass fraction of alpha-tocopherol in the edge zones. For further homogenisation, the cubes were stored in inert atmosphere at temperatures from 160 degrees C to 200 degrees C. In method 2, supercritical CO2 was used to incorporate the vitamin into the UHMW-PE. In an autoclave vessel, the cubes were treated with alpha-tocopherol dissolved in supercritical CO2 for several hours at temperatures from 100 degrees C to 170 degrees C. In both cases, the mass fraction of alpha-tocopherol was detected with the help of a FTIR-microscope. Both methods are well suited to stabilise crosslinked UHMW-PE with alpha-tocopherol. A stabilisation of the sensitive edge layer as well as a nearly homogenous distribution with varying alpha-tocopherol content may be realised by varying the process parameters. Using method 2, standard hip cups were stabilized nearly homogeneously with varying mass fraction of alpha-tocopherol. No oxidation of the UHMW-PE could be detected by infrared spectroscopy (FTIR) and HPLC studies showed a very low degradation of the alpha-tocopherol for both processes.

Concurrent low-dose cisplatin and thoracic radiotherapy in patients with inoperable stage III non-small cell lung cancer: a phase II trial with special reference to the hemoglobin level as prognostic parameter

PURPOSE

To evaluate the efficacy of concurrent radiochemotherapy in patients with stage III non-small cell lung cancer (NSCLC), and to examine the effect of hemoglobin levels on survival of those patients. The negative impact of anemia on survival has been noticed for other cancer sites including the head and neck, and the uterine cervix, but it has been rarely described in NSCLC cancer patients treated with radiotherapy.

METHODS

From April 1995 through March 2002, 56 patients with inoperable stage III non-small lung cancer were treated with radiotherapy consisting of 60 Gy (50 Gy+10 Gy boost) given in 30 fractions of 2 Gy daily, 5 days a week, over a period of 6 weeks, and concurrent low-dose daily chemotherapy (CHT) consisting of 6 mg/m(2) of cisplatin given Mondays-Fridays during weeks 1-2 and 5-6. All patients had stage III disease and ages ranged from 39 to 81 years old (median 63.9 years).

RESULTS

The 2-year and 3-year survival rates were 34% and 16%, respectively. Patients with a pretreatment hemoglobin level superior or equal to 11.6 g/dl had a 2-year survival rate of 52% as compared to 15.5% for patients with a pretreatment hemoglobin level inferior to 11.6 g/dl (p=0.0075). Patients with higher KI (>70%) showed better survival rates than those with lower KI. Surprisingly, patients in stage IIIA did not survive significantly longer than those in stage IIIB. Hematological toxicity (grade > or =2) prevailed (25%), followed by esophageal (5.4%) and bronchopulmonary (2%) toxicity. Only three patients experienced acute grade 3 hematological toxicity. Because of acute toxic effects, irradiation was interrupted in 8 patients (14.3%) for 7-13 days (median 7.5 days). Late high-grade (> or =3) toxicity was not found. No grade 4 toxicity or treatment-related deaths were observed during this study.

CONCLUSION

Our data show that concurrent radiotherapy with daily low dose cisplatin is well tolerated, and shows survival rates comparable to more aggressive treatment regimens. A combination of this chemotherapy with accelerated hyperfractionated radiotherapy might improve the results in the future. Furthermore, we could show that the hemoglobin levels prior to therapy have an influence on the prognosis, where lower levels were associated with worse outcome. Further trials should consider supplementation with erythropoietin.

Studies on the effect of electron beam radiation on the molecular structure of ultra-high molecular weight polyethylene under the influence of alpha-tocopherol with respect to its application in medical implants

Ultra-high molecular weight polyethylene (UHMW-PE) is being used successfully for articulating surfaces in joint endoprostheses, especially for cups of total hip endoprostheses. Sintered specimens containing various amounts of alpha-tocopherol (vitamin E) as a biocompatible stabilizer, were irradiated in nitrogen atmosphere as well as in air with various dosages of electron beam radiation. Size exclusion chromatography (SEC) was used to analyze the soluble fractions of the UHMW-PE samples according to their molecular weight distribution prior to and after irradiation. In nitrogen atmosphere the radiation-induced crosslinking showed to be dependent on the added amount of alpha-tocopherol in the sintered specimens. With an increasing content of alpha-tocopherol, the stabilizer acted as a scavenger for free radicals. Thus, the crosslinking was more and more hindered. The same effect was observed on the samples irradiated in air, where, in addition to the crosslinking process, oxidative molecular degradation occurred. The highest extent of crosslinked material was yielded with unstabilized samples in nitrogen atmosphere.

Tests of biocompatibility of alpha-tocopherol with respect to the use as a stabilizer in ultrahigh molecular weight polyethylene for articulating surfaces in joint endoprostheses

To inhibit the oxidation in vivo of hip-cups made of ultrahigh molecular weight polyethylene (UHMW-PE), the natural antioxidant alpha-tocopherol was added to the polymer. The added alpha-tocopherol may however undergo chemical transformations during manufacturing and sterilization by gamma-irradiation of hip-cups which may differ from human metabolism. Therefore, the question of the biocompatibility of the respective transformation products was investigated on test samples, which were prepared under the same conditions as applied for the production and sterilization of hip-cups. Thin plates (25 x 18 x 2 mm(3)) were fabricated out of test samples to investigate the cytotoxic activity according to EN 30993-5. In cytotoxicity testing, proliferation, mitochondrial activity and membrane integrity were not influenced by the material. In contrast, cell adhesion and cell spreading were diminished as shown with hemalum staining. In order to investigate the genotoxicity, the alpha-tocopherol and its transformation products were extracted from test specimens by n-heptane at 185 degrees C under nitrogen atmosphere. Then the n-heptane was evaporated in vacuo and the remaining alpha-tocopherol and its transformation products were dissolved in DMSO. The genotoxicity of this extract was then tested by the Ames-test according to DIN UA 12 (1995), which showed no indication for genotoxic activity.

Examination of the suitability of alpha-tocopherol as a stabilizer for ultra-high molecular weight polyethylene used for articulating surfaces in joint endoprostheses

The lifetime of articulating surfaces in joint endoprostheses made of ultra-high molecular weight polyethylene (UHMW-PE), especially of UHMW-PE-cups of hip-endoprostheses, is usually limited to 10-15 years due to material failure as a result of oxidation of the UHMW-PE in vivo. In this study the suitability of the natural antioxidant alpha-tocopherol (vitamin E) as a stabilizer for UHMW-PE in these applications was investigated. Specimens with 0.1%, 0.2%, 0.4% and 0.8% w/w alpha-tocopherol as well as unstabilized samples were sintered and sterilized with gamma-rays at 25 kGy in accordance with standard processing methods of cups for total hip-endoprostheses. These specimens were aged in pure oxygen at 70 degrees C and 5 bar as well as in aqueous H2O2 at 50 degrees C. The degree of oxidation was observed by means of FTIR-spectroscopy, DSC analysis and mechanical testing. The FTIR-measurements showed that alpha-tocopherol can prolong the lifetime of UHMW-PE in an oxidative environment by a factor of more than 2.5. In the mechanical tests no embrittlement could be observed with the stabilized samples. A comparison with the standard antioxidant system Irganox 1010/Irgafos 168 (Ciba-Geigy, Switzerland) was carried out and revealed that alpha-tocopherol can even exceed the stabilization effect of this widely-used antioxidant system.

Crystalline self-assembly into monolayers of folded oligomers at the air-water interface

Insertion of the 1,3-bis(ethynylene)benzene unit as a rigid spacer into a linear alkyl chain, thus separating the two resulting stems by 9 A. induces chain folding at the air-water interface. These folded molecules self-assemble into crystalline monolayers at this interface, with the plane of the folding unit almost perpendicular to the water surface, as determined by synchrotron grazing-incidence X-ray diffraction. Three distinct molecular shapes, of the types U, inverted U, and M, were obtained in the two-dimensional crystalline state, depending upon the number of spacer units, and the number and position of the hydrophilic groups in the molecule. The molecules form ribbons with a higher crystal coherence in the direction of stacking between the molecular ribbons, and a lower coherence along the ribbon direction. A similar molecule, but with a spacer unit that imposes a 5 A separation between alkyl chains, yields the conventional herringbone arrangement.

Elevated first-trimester serum relaxin concentrations in pregnant women following ovarian stimulation predict prematurity risk and preterm delivery

OBJECTIVE

To determine whether ovarian stimulation would result in higher circulating relaxin concentrations and whether this hyperrelaxinemia would be associated with prematurity.

METHODS

Two groups of women were studied: 1) women achieving pregnancy after ovarian stimulation (n = 114) and 2) women achieving pregnancy without treatment (n = 37). Serum was obtained at 6-12 weeks' gestational age; fetal number was determined by transvaginal ultrasound. Prematurity risk or preterm delivery was determined from the obstetric record. A specific human relaxin enzyme-linked immunosorbent assay was used to measure serum relaxin concentrations. Hyperrelaxinemia was defined as levels greater than 3 standard deviations above the weighted mean of levels in normal unstimulated singleton pregnancies at 6-12 weeks' gestation.

RESULTS

An association was found between prematurity risk or premature delivery and peripheral relaxin concentrations during weeks 6-12 of pregnancy in women having ovarian stimulation and in women having multiple gestations. Circulating relaxin concentrations greater than 16 ng/mL in women having ovarian stimulation and levels greater than 7 ng/mL in women who had multiple gestations predicted prematurity risk or premature delivery in 50% of the women.

CONCLUSIONS

These data demonstrate that after ovarian stimulation, some women have highly elevated circulating first-trimester relaxin concentrations. First-trimester hyperrelaxinemia identifies a group of women at risk for prematurity who can be monitored aggressively.

[Sonographic findings following laparoscopic cholecystectomy]

In a prospective study 500 patients were examined sonographically following laparoscopic cholecystectomy, 183 on several occasions. In the majority of patients (79.4%) there were no remarkable findings, either clinically or sonographically. In 102 patients (20.4%) there were sonographic abnormalities such as fluid collections in the gallbladder bed (13%), postoperative dilatation of the biliary passages (9.4%), free abdominal fluid (2%) or pleural effusions (1.2%). Only 25 patients (5%) showed clinical symptoms; there was complete agreement with the findings on ultrasound.

Extraction of difficult gallbladders by laparoscopic cholecystectomy: development of a new retrieval system

The retrieval of elusive or torn gallbladders or of those with large stones and lost calculi is often difficult and time-consuming. We developed an extractor to recover these difficult gallbladders and have already used this extraction method successfully in 26 patients.