Venous gas embolism as a predictive tool for improving CNS decompression safety

A key process in the pathophysiological steps leading to decompression sickness (DCS) is the formation of inert gas bubbles. The adverse effects of decompression are still not fully understood, but it seems reasonable to suggest that the formation of venous gas emboli (VGE) and their effects on the endothelium may be the central mechanism leading to central nervous system (CNS) damage. Hence, VGE might also have impact on the long-term health effects of diving. In the present review, we highlight the findings from our laboratory related to the hypothesis that VGE formation is the main mechanism behind serious decompression injuries. In recent studies, we have determined the impact of VGE on endothelial function in both laboratory animals and in humans. We observed that the damage to the endothelium due to VGE was dose dependent, and that the amount of VGE can be affected both by aerobic exercise and exogenous nitric oxide (NO) intervention prior to a dive. We observed that NO reduced VGE during decompression, and pharmacological blocking of NO production increased VGE formation following a dive. The importance of micro-nuclei for the formation of VGE and how it can be possible to manipulate the formation of VGE are discussed together with the effects of VGE on the organism. In the last part of the review we introduce our thoughts for the future, and how the enigma of DCS should be approached

Global patterns of plant leaf N and P in relation to temperature and latitude

A global data set including 5,087 observations of leaf nitrogen (N) and phosphorus (P) for 1,280 plant species at 452 sites and of associated mean climate indices demonstrates broad biogeographic patterns. In general, leaf N and P decline and the N/P ratio increases toward the equator as average temperature and growing season length increase. These patterns are similar for five dominant plant groups, coniferous trees and four angiosperm groups (grasses, herbs, shrubs, and trees). These results support the hypotheses that (i) leaf N and P increase from the tropics to the cooler and drier midlatitudes because of temperature-related plant physiological stoichiometry and biogeographical gradients in soil substrate age and then plateau or decrease at high latitudes because of cold temperature effects on biogeochemistry and (ii) the N/P ratio increases with mean temperature and toward the equator, because P is a major limiting nutrient in older tropical soils and N is the major limiting nutrient in younger temperate and high-latitude soils

The tibial tuberosity-trochlear groove distance; a comparative study between CT and MRI scanning

CT scan is the gold standard for the measurement of the tibial tuberosity-trochlear groove distance (TTTG). The aim of this study was to evaluate the reliability of the TTTG on MRI compared to CT scan. Twelve knees in 11 patients underwent CT and MRI examination for patellofemoral instability or anterior knee pain. Both the bony and the cartilaginous landmarks of the trochlear groove were used for the measurement of the TTTG. The measurements were performed by two experienced musculoskeletal radiologists. The interrater, intermethod and interperiod reliability was calculated using a restricted maximum likelihood estimation and a Bland-Altman analysis. The mean TTTG referenced on bony landmarks was 14.4+/-5.4 mm on CT scans, and 13.9+/-4.5 mm on MR images. The mean TTTG referenced on cartilaginous landmarks was 15.3+/-4.1 mm on CT scans, and 13.5+/-4.6 mm on MR images. An excellent interrater (82%), intermethods (86%), and interperiod (91%) quantitative reliability was found. TTTG can be determined reliably on MRI using either cartilage or bony landmarks. Additional CT scans are not necessary