Permanent night workers´ sleep and psychosocial factors in hospital work. A comparison to day and shift work

ABSTRACT

We aimed to study whether permanent night workers sleep and psychosocial factors differ from day workers and shift workers. The participants (n = 9 312, 92% females, average age 45 years, most commonly nurses and departmental secretaries) were day workers (DW, n = 2 672), shift workers (SW, n = 6 486) and permanent night workers (PNW, n = 154). The Finnish Public Sector survey responses from six hospital districts from 2012 were combined to payroll data from 91 days preceding the survey. The data were analyzed using Pearson χ²-test, one-way ANOVA and multinomial logistic regression analysis. The PNWs reported slightly longer average sleep length than the SWs or the DWs (7:27 vs. 7:13 and 7:10 h, p < 0.001). The PNWs reported least often difficulties in maintaining sleep (p < 0.001) compared to the SWs and the DWs. The PNWs reported most often difficulties to fall asleep and fatigue during free-time (p-values <0.001). The DWs and PNWs experienced less often work-life conflict than the SWs (25 and 26 vs. 38%, p < 0.001). The PNWs were more often satisfied with autonomy at work and appreciation and fair treatment by colleagues than the DWs or the SWs (p < 0.001). The SWs and PNWs reported remarkably higher occurrence of verbal (p < 0.001, OR 3.71, 95% CI 3.23–4.27 and OR 7.67, 95% CI 5.35–10.99, respectively) and physical workplace violence (p < 0.001, OR 9.24, 95% CI 7.17–11.90 and OR 28.34, 95% CI 16.64–43.06, respectively) compared to DWs. Conclusively, PNWs reported contradictory differences in sleep quality compared to DWs and SWs. PNWs are more often satisfied with their colleagues and autonomy at work than DWs or SWs but face workplace violence remarkably more often.     

The association of sleepiness,insomnia, sleep disturbance and pain: a study amongst shiftworking nurses

Sleep and Biological Rhythms - Sleep problems are commonly associated with chronic pain. It is not known whether pain is more related to a particular type of sleep problem or to more composite...     

Physiological Concentration of Exogenous Lactate Reduces Antimycin A Triggered Oxidative Stress in Intestinal Epithelial Cell Line IPEC-1 and IPEC-J2 In Vitro

Weaning triggers an adaptation of the gut function including luminal lactate generation by lactobacilli, depending on gastrointestinal site. We hypothesized that both lactobacilli and lactate influence porcine intestinal epithelial cells. In vivo experiments showed that concentration of lactate was significantly higher in gastric, duodenal and jejunal chyme of suckling piglets compared to their weaned counterparts. In an in vitro study we investigated the impact of physiological lactate concentration as derived from the in vivo study on the porcine intestinal epithelial cells IPEC-1 and IPEC-J2. We detected direct adherence of lactobacilli on the apical epithelial surface and a modulated F-actin structure. Application of lactobacilli culture supernatant alone or lactate (25 mM) at low pH (pH 4) changed the F-actin structure in a similar manner. Treatment of IPEC cultures with lactate at near neutral pH resulted in a significantly reduced superoxide-generation in Antimycin A-challenged cells. This protective effect was nearly completely reversed by inhibition of cellular lactate uptake via monocarboxylate transporter. Lactate treatment enhanced NADH autofluorescence ratio (F_cytosol/F_nucleus) in non-challenged cells, indicating an increased availability of reduced nucleotides, but did not change the overall ATP content of the cells. Lactobacilli-derived physiological lactate concentration in intestine is relevant for alleviation of redox stress in intestinal epithelial cells.     

Age-related variations in acyl-CoA:retinol acyltransferase activity and vitamin A concentration in the liver and epidermis of hairless mice

Since the factors regulating retinol esterification by acyl-CoA:retinol acyltransferase are poorly understood, we studied the age-related variations in acyl-CoA:retinol acyltransferase activity in hairless mice. Epidermis and liver were collected at intervals from birth to adolescence (0-6 weeks). Vitamin A was analyzed by high-performance liquid chromatography and acyl-CoA:retinol acyltransferase by an in vitro radioincubation assay of microsomes. Epidermal vitamin A (retinol plus retinyl esters) increased 8-10 times after birth and by the age of 3 weeks adult values were attained. This increase was accompanied by a 2-fold increase in acyl-CoA:retinol acyltransferase activity in the epidermis between 3 days and 6 weeks of age. In young animals the dependence of acyl-CoA:retinol acyltransferase on exogenous co-substrate (palmitoyl-CoA) was also lower than in adult animals. Although a pronounced age-related accumulation of retinol was recorded in the liver, the activity of acyl-CoA:retinol acyltransferase did not increase with age and there was no change in the dependence of acyl-CoA:retinol acyltransferase on exogenous palmitoyl-CoA.     

The Effects of Atorvastatin Therapy on Rheological Characteristics of Erythrocyte Membrane, Serum Lipid Profile and Oxidative Status in Patients with Dyslipidemia

The statins, most commonly used in the treatment of hyperlipidemia, have certain beneficial effects including improved endothelial function, plaque stability and decreased oxidative stress and inflammation, beyond their lipid-lowering effect in plasma. We evaluated the pleiotropic impact of atorvastatin on erythrocyte structural/mechanical properties and lipid peroxidation in dyslipidemics. The study group included 44 patients with dyslipidemia and was divided into subgroups according to triglyceride and cholesterol levels as hypercholesterolemic (n?=?29) and mixed-type hyperlipidemic (n?=?15). Subjects were given 10?mg atorvastatin per day for 12?weeks. Changes in serum lipid composition, lipid contents, Na⁺/K⁺-ATPase activity and osmotic fragility in erythrocytes and oxidative stress parameters of erythrocytes and plasma were studied. Atorvastatin therapy improved the serum lipid profile of both subgroups. This alteration was accompanied by a decreased level of cholesterol in erythrocyte membranes. Moreover, enhanced activity of Na⁺/K⁺-ATPase in erythrocytes reflected the improvements in membrane lipids of both subgroups. However, a significant change was observed in osmotic fragility values of the mixed-typed dyslipidemic group. This treatment lowered the lipid peroxidation in plasma and erythrocytes and increased plasma total antioxidant capacity in all groups. The present study shows that the use of atorvastatin reversed the structural and functional features of erythrocyte membranes in dyslipidemic subjects. Also, hypolipidemic therapy had a beneficial impact on a balance between oxidant and antioxidant systems.     

Cytokinins regulate a bidirectional phosphorelay network in Arabidopsis

The cytokinin class of plant hormones plays key roles in regulating diverse developmental and physiological processes. Arabidopsis perceives cytokinins with three related and partially redundant receptor histidine kinases (HKs): CRE1 (the same protein as WOL and AHK4), AHK2, and AHK3 (CRE-family receptors). It is suggested that binding of cytokinins induces autophosphorylation of these HKs and subsequent transfer of the phosphoryl group to a histidine phosphotransfer protein (HPt) and then to a response regulator (RR), ultimately regulating downstream signaling events. Here we demonstrate that, in vitro and in a yeast system, CRE1 is not only a kinase that phosphorylates HPts in the presence of cytokinin but is also a phosphatase that dephosphorylates HPts in the absence of cytokinin. To explore the roles of these activities in planta, we replaced CRE1 with mutant versions of the gene or with AHK2. Replacing CRE1 with CRE1(T278I), which lacks cytokinin binding activity and is locked in the phosphatase form, decreased cytokinin sensitivity. Conversely, replacing CRE1 with AHK2, which favors kinase activity, increased cytokinin sensitivity. These results indicate that in the presence of cytokinins, cytokinin receptors feed phosphate to phosphorelay-integrating HPt proteins. In the absence of cytokinins, CRE1 removes phosphate from HPt proteins, decreasing the system phosphoload.     

Liposome-based homogeneous luminescence resonance energy transfer

There is an increasing need for developing simple assay formats for biomedical screening purposes. Assays on cell membranes have become important in studies of receptor-ligand interactions and signal pathways. Here luminescence energy transfer was studied on liposomes containing europium ion chelated to 4,4,4-trifluoro-1-(2-naphthalenyl)-1,3-butanedione and trioctylphosphine oxide. Energy transfer efficiency was characterized with biotin-streptavidin interaction, and a model assay concept for a homogeneous time-resolved luminescence resonance energy transfer (LRET) assay was developed. Acceptor-labeled streptavidin was bound to biotinylated lipids on the liposomes, leading to close proximity of the LRET pair. The liposome-based LRET assay was optimized for dye incorporation and concentration, biotinylation degree, liposome size, and kinetics. Sensitivity for a competitive biotin assay was at a picomolar range with a coefficient of variation from 7 to 20%. The developed lipid membrane-based system was feasible in separation free LRET assay concept with high sensitivity, indicating that the assay principle can potentially be used for biologically more relevant target molecules.     

Sleep Restriction Increases the Risk of Developing Cardiovascular Diseases by Augmenting Proinflammatory Responses through IL-17 and CRP

Background

Sleep restriction, leading to deprivation of sleep, is common in modern 24-h societies and is associated with the development of health problems including cardiovascular diseases. Our objective was to investigate the immunological effects of prolonged sleep restriction and subsequent recovery sleep, by simulating a working week and following recovery weekend in a laboratory environment.

Methods and Findings

After 2 baseline nights of 8 hours time in bed (TIB), 13 healthy young men had only 4 hours TIB per night for 5 nights, followed by 2 recovery nights with 8 hours TIB. 6 control subjects had 8 hours TIB per night throughout the experiment. Heart rate, blood pressure, salivary cortisol and serum C-reactive protein (CRP) were measured after the baseline (BL), sleep restriction (SR) and recovery (REC) period. Peripheral blood mononuclear cells (PBMC) were collected at these time points, counted and stimulated with PHA. Cell proliferation was analyzed by thymidine incorporation and cytokine production by ELISA and RT-PCR. CRP was increased after SR (145% of BL; p<0.05), and continued to increase after REC (231% of BL; p<0.05). Heart rate was increased after REC (108% of BL; p<0.05). The amount of circulating NK-cells decreased (65% of BL; p<0.005) and the amount of B-cells increased (121% of BL; p<0.005) after SR, but these cell numbers recovered almost completely during REC. Proliferation of stimulated PBMC increased after SR (233% of BL; p<0.05), accompanied by increased production of IL-1β (137% of BL; p<0.05), IL-6 (163% of BL; p<0.05) and IL-17 (138% of BL; p<0.05) at mRNA level. After REC, IL-17 was still increased at the protein level (119% of BL; p<0.05).

Conclusions

5 nights of sleep restriction increased lymphocyte activation and the production of proinflammatory cytokines including IL-1β IL-6 and IL-17; they remained elevated after 2 nights of recovery sleep, accompanied by increased heart rate and serum CRP, 2 important risk factors for cardiovascular diseases. Therefore, long-term sleep restriction may lead to persistent changes in the immune system and the increased production of IL-17 together with CRP may increase the risk of developing cardiovascular diseases.