The impact of shift work induced chronic circadian disruption on IL-6 and TNF-alpha immune responses.

AIM: Sleep disturbances induce proinflammatory immune responses, which might increase cardiovascular disease risk. So far the effects of acute sleep deprivation and chronic sleep illnesses on the immune system have been investigated. The particular impact of shift work induced chronic circadian disruption on specific immune responses has not been addressed so far. METHODS: Pittsburgh-Sleep-Quality-Index (PSQI) questionnaire and blood sampling was performed by 225 shift workers and 137 daytime workers. As possible markers the proinflammatory cytokines IL-6 and TNF-alpha and lymphocyte cell count were investigated. A medical examination was performed and biometrical data including age, gender, height, weight, waist and hip circumference and smoking habits were collected by a structured interview. RESULTS: Shift workers had a significantly higher mean PSQI score than day workers (6.73 vs. 4.66; p < 0.001). Day workers and shift workers had similar serum levels of IL-6 (2.30 vs. 2.67 resp.; p = 0.276), TNF-alpha (5.58 vs. 5.68, resp.; p = 0.841) or lymphocytes count (33.68 vs. 32.99, resp.; p = 0.404). Furthermore there were no differences in cytokine levels (IL-6 p = 0.761; TNF-alpha p = 0.759) or lymphocyte count (p = 0.593) comparing the sleep quality within the cohorts. When this calculation of sleep quality was stratified by shift and day workers irrespective of their sleep quality day workers and shift workers had similar serum levels of IL-6, TNF-alpha or lymphocytes count. Multiple linear regression analysis showed a significant correlation of lymphocytes count and smoking habits. CONCLUSION: Shift work induces chronic sleep debt. Our data reveals that chronic sleep debt might not always lead to an activation of the immune system, as we did not observe differences in lymphocyte count or level of IL-6 or TNF-alpha serum concentration between shift workers and day workers. Therefore chronic sleep restriction might be eased by a long-term compensating immune regulation which (in healthy) protects against an overstimulation of proinflammatory immune mechanisms and moderates metabolic changes, as they are known from short-term sleep deprivation or sleep related breathing disorders.

Correlates shift work with increased risk of gastrointestinal complaints or frequency of gastritis or peptic ulcer in H. pylori-infected shift workers?

AIM: There is an ongoing discussion whether work under shift work conditions enhances the ulcerogenic potential of Helicobacter pylori infections. This may be induced by a disruption of the circadian rhythm. The present study assessed whether there is an association between H. pylori infection and an increased risk of gastrointestinal complaints or frequency of gastritis or peptic ulcer in H. pylori-infected shift workers. METHODS: We analyzed 615 workers divided in shift and daytime. Upper gastrointestinal diseases, medication or operation, unspecific gastrointestinal complaints, smoking habits, subjective job strain and private stress factors were monitored. The H. pylori status was analyzed using IgA and IgG antibody concentration in blood and qualitative ELISA for feces. RESULTS: It was observed that 27.6% of all workers, 34.6% of the shift workers and 16% of daytime workers were Hp positive (P = 0.004). Shift workers reported reflux or pyrosis less frequently than daytime workers. No increased lifetime prevalence for gastritis, ulcus or eradication therapy was found for shift workers. Analysis revealed a weak regression between age and Hp-positive gastritis or upper gastrointestinal complaints, smoking habits were a major confounding factor for ulcus disease. Clinical manifestation of gastritis or ulcus disease did not correlate with shift work or especially shift work including night work. CONCLUSIONS: As a result of the present study, it cannot be confirmed that there is a causal connection between shift work and upper or unspecific gastrointestinal complaints or gastritis or peptic ulcer in dependency of a H. pylori colonization.

Outpatient rehabilitation of workers with musculoskeletal disorders using structured workplace description.

OBJECTIVES: In most industrialized countries musculoskeletal disorders contribute considerably (25%) to illness induced work absence. A special interest to reduce worker absences exists in highly specialized industries such as jet manufacturing, where specific knowledge is hard to replace. We investigated the reduction and sustainability in sick leave days by a workplace oriented outpatient rehabilitation program based on structured information exchange between occupational physicians and therapists. METHODS: Sick leave days reduction and return-to-work-ratios were analysed for 79 male blue collar workers with musculoskeletal disease, who voluntarily participated in an outpatient rehabilitation treatment between 2002 and 2005. During rehabilitation therapy standardized workplace descriptions were given to the therapists and individual return-to-work (rtw) schemes were implemented. Therapy lasted from 3 to 4 weeks followed by workplace reintegration. Off-work-time was calculated from 0 to 6 years before and 0 to 3 years after rehabilitation from insurance and industrial medical reports. RESULTS: A total of 97% of the patients returned to their original job at the workplace, usually directly after the rehabilitation. Average sick leave days per year were reduced from 48.8 +/- 32.8 days before to 34.2 +/- 37.3 days after the rehabilitation. The therapy interrupted an increase in sick leave days over the years stabilizing absence at a low level for at least 2 years. Duration of illness related work absence was the only significant predictor for sick leave reduction (P < 0.05). Other common risk factors for musculoskeletal diseases like smoking or body mass index did not significantly influence the therapeutic effect. CONCLUSIONS: Our results support evidence that information exchange for workplace description and rehabilitation therapist may help to reduce sick leave days and achieve very high rtw-ratio. However it is important to observe the effects of this shared information for longer intervals.

Shift work and pathological conditions.

Shift work exerts major influences on the physiological functions of the human body. These are primarily mediated by the disruption of circadian rhythms since most body functions are circadian rhythmic. Next to the disturbances caused by changes in the circadian system, shift work has also been suggested to be related to a number of other health disorders. The present study summarizes recently published data on the potential relationship between disorders and shift working.

Fibrogranular bodies, annulate lamellae, and polyribosomes in the dragonfly oocyte.

Discrete and multiple cytoplasmic regions become apparent during oogenesis in the dragonfly oocyte that are thought to arise from the nucleus (nucleolus) earlier in development, and on the basis of previous cytochemical tests, they are believed to contain ribonucleoprotein. These distinct cytoplasmic regions have been called fibrogranular bodies since they are composed of (1) a multitude of small granules ( ∼ 6-16 nm) and (2) interconnected fibrillar elements ( ∼ 2-4 nm wide). Since the fibrogranular bodies have not been isolated, they have not been biochemically characterized and their composition is unknown. However, it has been suggested that this material, in part based on other studies, may represent stored developmental information, perhaps including mRNA, rRNA, and protein. Prior to vitellogenesis, but continuing throughout the process, annulate lamellae progressively differentiate within the fibrogranular bodies. After annulate lamellae have differentiated inside the fibrogranular bodies, many of the lamellae extend into the surrounding cytoplasm as elements of rough-surfaced endoplasmic reticulum (rER). There appears to be a gradual dispersal of material as more and more annulate lamellae form within the fibrogranular bodies such that very late in oogenesis, it is difficult to observe the fibrogranular material. However, extensive numbers of polyribosomes and many parallel lamellae of rER are present. The variations noted with respect to the polyribosomes, fibrogranular bodies, and pores of the annulate lamellae suggest that pores of annulate lamellae are important in the processing or activation of "stored information" for subsequent development, perhaps including a role in polyribosomal assembly.

Differentiation of Acmaea digitalis oocytes with special reference to lipid-endoplasmic reticulum-annulate lamellae-polyribosome relationships.

During initial stages of oogenesis, many nucleoli are adpressed to the inner membrane of the nuclear envelope. Small nucleolar fragments appear to traverse the pores of the nuclear envelope and accumulate in the perinuclear ooplasm as fibrogranular bodies. Mitochondria become closely associated with some of the fibrogranular bodies. In addition to ribosomes and polyribosomes that are present in small oocytes, lamellae of rough-surfaced endoplasmic reticulum (rER) increase greatly in number during early stages of differentiation. Some individual lamellae are attached at their ends to the outer membrane of the nuclear envelope. Many parallel lamellae of rER are then encountered as well as numerous circular profiles consisting of concentric loops of rER. Soon after the differentiation of the extensive system of rER, lipid droplets or spheres appear in the ooplasm and they are initially surrounded by many circular, concentric lamellae of rER. Initially, the number of concentric lamellae of rER surrounding a lipid droplet may vary from less than a dozen to more than two dozen. During middle and late phases of vitellogenesis, most of the lipid spheres that comprise the most numerous and significant component of the yolk are surrounded by only one or two concentric lamellae of rER (in some cases the lamellae are part rough-surfaced and part smooth-surfaced). In addition, annulate lamellae are then observed to be associated with a portion of the lipid droplet surface. The number of annulate lamellae that extend focally from the lipid sphere distally into the cytoplasm is variable; often two or three to more than a dozen lamellae. Small granules, many of which range from 6 to 12 nm and thin fibrils (approximately 2-3 nm in width) may be associated with the annulate lamellae. In addition, polyribosomes frequently appear to be continuous with the pore-associated material of the annulate lamellae. The ends of some annulate lamellae may extend as lamellae of the rER. The morphologic relationships and relationships and variations observed between the lipid droplets, rER, annulate lamellae, and polyribosomes during lipidogenesis in this oocyte are interpreted to support a recent hypothesis (Kessel, 1981a,b) that the pores of annulate lamellae may be involved in some manner with the processing of ribosomal subunits or precursors into functioning polyribosomes, and that their appearance in specific association with the surface of many lipid spheres and rER in the oocyte late in vitellogenesis may be related to the formation of additional functional polyribosomes necessary to complete the final synthesis of many lipid droplets that are present in the ooplasm of the full-grown oocyte.