Effects of 6/6 and 4/8 watch systems on sleepiness among bridge officers

During the last ten years, severe sleepiness or falling asleep by watch keeping officers has been a direct or a contributing factor in a number of maritime accidents. This study examined the relationship between two watch systems and its impact on fatigue and sleepiness in bridge officers. A questionnaire and a sleep/work diary were sent to a representative sample of the Finnish Maritime Officer Association. In all, 185 bridge officers answered the questionnaire on sleep, work hours, and safety, including the Skogby Excessive Daytime Sleepiness index (SEDS); 42% of the bridge officers worked two 4 h watches (4/8) per day, while 26% worked two 6 h watches per day (6/6). Ninety-five of the participants completed a sleep diary for seven consecutive days while at sea. The timing of the watch duties and sleep was recorded, as was subjective sleepiness every 2 h using the Karolinska Sleepiness Scale (KSS). 17.6% of the participants had fallen asleep at least once while on duty during their career. Compared to the 4/8 watch system, the officers working the 6/6 watch system reported shorter sleep durations, more frequent nodding-off on duty (7.3% vs. 1.5%), and excessive sleepiness (32% vs. 16% with SEDS>14). Based on a logistic regression analysis, high SEDS was significantly related with probable obstructive sleep apnea (OR 5.7), the 6/6 watch system (OR 4.0), and morningness-eveningness while controlling simultaneously several individual and sleep-related factors. Subjective sleepiness (KSS) was highest at 04:00 and 06:00 h. In a multivariate analysis, the KSS was significantly related to time of day, time after awaking, sleep length, and interactions of the watch systems with age, morningness-eveningness, and Epworth sleepiness scale (ESS) score. Severe sleepiness at 04:00-06:00 h was especially problematic in the 6/6 watch system among evening types and among the bridge officers with high ESS. The results suggest the 6/6 watch system is related to a higher risk of severe sleepiness during the early morning hours compared to the 4/8 and the other watch systems assessed.     

Effects of 6/6 and 4/8 Watch Systems on Sleepiness among Bridge Officers

During the last ten years, severe sleepiness or falling asleep by watch keeping officers has been a direct or a contributing factor in a number of maritime accidents. This study examined the relationship between two watch systems and its impact on fatigue and sleepiness in bridge officers. A questionnaire and a sleep/work diary were sent to a representative sample of the Finnish Maritime Officer Association. In all, 185 bridge officers answered the questionnaire on sleep, work hours, and safety, including the Skogby Excessive Daytime Sleepiness index (SEDS); 42% of the bridge officers worked two 4 h watches (4/8) per day, while 26% worked two 6 h watches per day (6/6). Ninety‐five of the participants completed a sleep diary for seven consecutive days while at sea. The timing of the watch duties and sleep was recorded, as was subjective sleepiness every 2 h using the Karolinska Sleepiness Scale (KSS). 17.6% of the participants had fallen asleep at least once while on duty during their career. Compared to the 4/8 watch system, the officers working the 6/6 watch system reported shorter sleep durations, more frequent nodding‐off on duty (7.3% vs. 1.5%), and excessive sleepiness (32% vs. 16% with SEDS>14). Based on a logistic regression analysis, high SEDS was significantly related with probable obstructive sleep apnea (OR 5.7), the 6/6 watch system (OR 4.0), and morningness‐eveningness while controlling simultaneously several individual and sleep‐related factors. Subjective sleepiness (KSS) was highest at 04:00 and 06:00 h. In a multivariate analysis, the KSS was significantly related to time of day, time after awaking, sleep length, and interactions of the watch systems with age, morningness‐eveningness, and Epworth sleepiness scale (ESS) score. Severe sleepiness at 04:00–06:00 h was especially problematic in the 6/6 watch system among evening types and among the bridge officers with high ESS. The results suggest the 6/6 watch system is related to a higher risk of severe sleepiness during the early morning hours compared to the 4/8 and the other watch systems assessed.     

Salivary Biomarkers for Detection of Systemic Diseases

Background and Objective

Analysis of inflammatory biomarkers in saliva could offer an attractive opportunity for the diagnosis of different systemic conditions specifically in epidemiological surveys. The aim of this study was to investigate if certain salivary biomarkers could be used for detection of common systemic diseases.

Materials and Methods

A randomly selected sample of 1000 adults living in Skåne, a county in the southern part of Sweden, was invited to participate in a clinical study of oral health. 451 individuals were enrolled in this investigation, 51% women. All participants were asked to fill out a questionnaire, history was taken, a clinical examination was made and stimulated saliva samples were collected. Salivary concentrations of IL-1β, -6, -8, TNF-α, lysozyme, MMP-8 and TIMP-1 were determined using ELISA, IFMA or Luminex assays.

Results

Salivary IL-8 concentration was found to be twice as high in subjects who had experience of tumour diseases. In addition, IL-8 levels were also elevated in patients with bowel disease. MMP-8 levels were elevated in saliva from patients after cardiac surgery or suffering from diabetes, and muscle and joint diseases. The levels of IL-1β, IL-8 and MMP-8, as well as the MMP-8/TIMP-1 ratio were higher in subjects with muscle and joint diseases.

Conclusion

Biomarkers in saliva have the potential to be used for screening purposes in epidemiological studies. The relatively unspecific inflammatory markers used in this study can not be used for diagnosis of specific diseases but can be seen as markers for increased systemic inflammation.     

Matrix metalloproteinase-8 regulates transforming growth factor-β1 levels in mouse tongue wounds and fibroblasts in vitro

Matrix metalloproteinase-8 (MMP-8)-deficient mice (Mmp8-/-) exhibit delayed dermal wound healing, but also partly contradicting results have been reported. Using the Mmp8-/- mice we investigated the role of MMP-8 in acute wound healing of the mobile tongue, and analyzed the function of tongue fibroblasts in vitro. Interestingly, in the early phase the tongue wounds of Mmp8-/- mice healed faster than those of wild type (wt) mice resulting in significant difference in wound widths (P=0.001, 6–24 h). The Mmp8-/- wounds showed no change in myeloperoxidase positive myeloid cell count, but the level of transforming growth factor (TGF)-β1 was significantly increased (P=0.007) compared to the wt tongues. Fibroblasts cultured from wt tongues expressed MMP-8 and TGF-β1. However, higher TGF-β1 levels were detected in Mmp8-/- fibroblasts, and MMP-8 treatment decreased phosphorylated Smad-2 levels and α-smooth muscle actin expression in these fibroblasts suggesting reduced TGF-β1 signaling. Consistently, a degradation of recombinant TGF-β1 by MMP-8 decreased its ability to activate the signaling cascade in fibroblasts. Moreover, collagen gels with Mmp8-/- fibroblasts reduced more in size. We conclude that MMP-8 regulates tongue wound contraction rate and TGF-β1 levels. In vitro analyses suggest that MMP-8 may also play a role in regulating TGF-β1 signaling of stromal fibroblasts.     

Changes in feeding level during early pregnancy affect fertility in gilts

Modified feeding combining the benefits of restricted feeding after ovulation and abundant feeding during implantation in autumn was tested. Three groups of eight gilts were housed with individual feeding stalls and fed 40 MJ per day of a commercial ration. Following insemination gilts were fed 27 MJ per day (LLL) or 54 MJ per day (HHH) for 34 days or 27 MJ per day for 10 days, 54 MJ per day for 7 days followed by 27 MJ per day until day 34 (LHL). Blood for progesterone analysis was collected daily during the week of ovulation and then twice a week until the end of the study. For LH assay, blood was collected from five gilts from each group at 15 min interval for 10 h on the day 15 of pregnancy. Gilts were weighed three times at intervals of 4 weeks. The effect of dietary treatment was significant (P<0.05) on body weight gain from days 0 to 30 of pregnancy, 1201, 287 and 438 g per day for groups HHH, LLL and LHL respectively. The pregnancy rate at day 34 was significantly higher (P<0.005) in HHH-group (100%) compared with LLL (25%) and LHL (38%) although HHH group had significantly lower (P<0.05) progesterone concentration on days 9 and 12. The basal LH level was significantly higher (P<0.01) in HHH group compared to LHL group (mean±S.D.) (0.98±0.22 and 0.60±0.08, respectively). Gilts in HHH group had a significantly higher mean LH concentration (1.18±0.24) than those in group LHL (0.7±0.07) (P<0.05), but not in group LLL (0.93±0.15) (P=0.09). There was a tendency (P=0.058) for amplitude to be higher for gilts in HHH group. The LHL feeding strategy did not provide the benefits anticipated. Instead, it was the HHH feeding strategy that provided a disfinct advantage in pregnancy rate. The mechanism mediating supportive effect of high feeding level on the maintenance of early pregnancy is yet to be determined.     

Partial purification and characterization of latent human leukocyte collagenase

Latent and active collagenase were extracted from human polymorphonuclear leukocytes. Separation of the two forms of the enzyme was performed by gel filtration on Sepharose 6 B. The latent form of the enzyme was detected from chromatographic fractions after a brief treatment with trypsin or exposure of the fractions to the sulfhydryl reagent phenylmercuric chloride. Latent enzyme eluted before active enzyme from the column, indicating a higher apparent molecular weight. Partially purified latent enzyme exhibited an apparent molecular size of 70-75 kDa as estimated by gel filtration. A value of 50-55 kDa was obtained for active enzyme. Without activation the latent enzyme did not degrade soluble collagen substrate. This was demonstrated by a quantitative viscometric assay and also by sodium dodecyl sulfate polyacrylamide gel electrophoresis, when no typical cleavage products of collagen could be seen. Latent enzyme could not be obtained unless serine protease inhibitors were present during the extraction and purification procedures. The effects of the activators trypsin, phenylmercuric chloride, phenylmethyl sulfonyltrypsin, and N-ethylmaleimide on the latent human polymorphonuclear leukocyte collagenase were studied. Contrary to the suggestion that inactive proteases activate latent human polymorphonuclear leukocyte collagenase, the inactive phenylmethyl sulfonyl-trypsin could not activate latent collagenase.