Fast hyperbaric decompression after heliox saturation altered the brain proteome in rats.

Better understanding of the physiological mechanisms and neurological symptoms involved in the development of decompression sickness could contribute to improvements of diving procedures. The main objective of the present study was to determine effects on the brain proteome of fast decompression (1 bar/20 s) compared to controls (1 bar/10 min) after heliox saturation diving, using rats in a model system. The protein S100B, considered a biomarker for brain injury, was not significantly different in serum samples from one week before, immediately after, and one week after the dive. Alterations in the rat brain proteome due to fast decompression were investigated using both iontrap and orbitrap LC-MS, and 967 and 1062 proteins were quantified, respectively. Based on the significantly regulated proteins in the iontrap (56) and orbitrap (128) datasets, the networks "synaptic vesicle fusion and recycling in nerve terminals" and "translation initiation" were significantly enriched in a system biological database analysis (Metacore). Ribosomal proteins (RLA2, RS10) and the proteins hippocalcin-like protein 4 and proteasome subunit beta type-7 were significantly upregulated in both datasets. The heat shock protein 105 kDa, Rho-associated protein kinase 2 and Dynamin-1 were significantly downregulated in both datasets. Another main effect of hyperbaric fast decompression in our experiment is inhibition of endocytosis and stimulation of exocytosis of vesicles in the presynaptic nerve terminal. In addition, fast decompression affected several proteins taking parts in these two main mechanisms of synaptic strength, especially alteration in CDK5/calcineurin are associated with a broad range of neurological disorders. In summary, fast decompression after heliox saturation affected the brain proteome in a rat model for diving, potentially disturbing protein homeostasis, e.g. in synaptic vesicles, and destabilizing cytoskeletal components. Data are available via ProteomeXchange with identifier PXD006349.

MRI of the central nervous system in rats following heliox saturation decompression.

AIMS: The main objectives of the present study was to establish an animal model of decompression sickness (DCS) after heliox saturation diving, and to use this model to evaluate possible morphological changes in the CNS induced by DCS using structural MRI. METHODS: Two groups of rats were pressurized with heliox to 5 bar (pO2 = 50 kPa). The saturation time was three hours; decompression rate was 1 bar/10 seconds or 1 bar/20 seconds. A 7.0 Tesla small animal MRI scanner was used for detection of possible morphological changes in the brain and spinal cord, two hours and one week after the dive, compared to one week prior to the dive. RESULTS: Neurological symptoms of DCS were observed in seven out of 10 animals. MRI of the brain and spinal cord did not reveal any morphological CNS injuries. CONCLUSION: This diving procedure was successful in causing DCS in a large proportion of the animals. However, despite massive neurological signs of DCS, no visible CNS injuries were observed in the MRI scans.

Safety in pediatric imaging: an update.

Many assumptions are made when imaging children. In particular a judgement is made regarding how safe or unsafe each imaging modality is, using relatively arbitrary definitions and distinctions, due to the lack of robust scientific data. Here, the latest evidence is reviewed, particularly regarding the medical exposure to ionizing radiation (X-rays and CT) and MRI in childhood. The best evidence currently available suggests a small but convincing risk of cumulative low-dose ionizing radiation in children. Given our predictions for the children imaged today, it seems reasonable to pursue non-ionizing-based techniques wherever possible, although there is emerging evidence that MRI and ultrasound may have hitherto unknown effects. As our knowledge base expands, we must continually review our practice in light of the latest scientific data.

[Are sleep difficulties in night work a problem for the offshore industry?]. / Er søvnvansker ved nattarbeid et problem for offshoreindustrien?

BACKGROUND: Shift work is increasingly used in industry and services; in the Norwegian offshore industry approximately 6750 employees work night shifts. We wanted to look into the implications of night shifts on sleep and circadian rhythm, with particularly focus on the offshore sector. MATERIAL AND METHODS: We conducted literature searches on Medline, covering the period from 1966 to 2003; only eight studies pertaining to the offshore activity in the North Sea with emphasis on sleep and night work were identified. RESULTS: Night shifts on oil platforms were associated with sleeping difficulties. The isolated setting on the installations in the North Sea probably facilitates biological adaptation to night work compared to work onshore. Light therapy has a documented effect for re-adaptation to normal daytime functioning upon returning home. INTERPRETATION: Night work disturbs sleep. The level of functioning during the first night shifts is probably lower than the optimal level of functioning. Only a few studies of adaptation to night work in the offshore industry have been conducted and little research has been done concerning swing shifts in the North Sea. The field is obviously in need of more empirically based knowledge.

[Shift work and accidents--relevance for the offshore industry]. / Skiftarbeid og ulykker--relevans for offshoreindustrien.

BACKGROUND: Increased use of shift work depends on keeping productivity and safety at acceptable levels. Approximately 7000 workers in the Norwegian offshore industry are working night shifts. MATERIAL AND METHODS: We have reviewed relevant literature on injuries in relation to shift work. RESULTS: The literature is inconclusive. The reason for this is most likely that all the studies are either observational or retrospective; no controlled interventions were found. However, shift work generally and night shifts in particular seem to increase the risk of injury. When newer data are taken into account, these clearly indicate that shift work is associated with reduced safety and productivity. INTERPRETATION: We conclude that if and when shift work is needed, it should be organised with certain patterns and rest breaks in order to reduce the risk of accidents and injuries. Focused and well-planned research is strongly needed in this field. Very few studies have been conducted on shift work and health effects offshore.