Southern ocean carbon and heat impact on climate.

The Southern Ocean greatly contributes to the regulation of the global climate by controlling important heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on decadal timescales are therefore impacted by oceanic processes taking place in the Southern Ocean, yet too little is known about these processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent processes at scales that are not well captured in current Earth system models. The Southern Ocean Carbon and Heat Impact on Climate programme was launched to address this knowledge gap, with the overall objective to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key physical processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches. Here, we provide a brief overview of the programme, as well as a summary of some of the scientific progress achieved during its first half. Advances range from new evidence of the importance of specific processes in Southern Ocean ventilation rate (e.g. storm-induced turbulence, sea-ice meltwater fronts, wind-induced gyre circulation, dense shelf water formation and abyssal mixing) to refined descriptions of the physical changes currently ongoing in the Southern Ocean and of their link with global climate. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.

A sea change in our view of overturning in the subpolar North Atlantic.

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

Preservation of embryonic kidneys for transplantation.

BACKGROUND: Long-term storage of embryonic kidneys is crucial for the organization of transplantation and organ banking. In this study, we investigated the effects of controlled-rate freezing and ice-free vitrification on metanephroi (MN) viability. METHODS: Metanephroi isolated from 15-day (E15) timed pregnant Lewis rats were either: (i) frozen, using a DMSO/FCS/RPMI solution and a controlled freezing rate of -0.3 degrees C/min, from -10 degrees to -40 degrees C; or (ii) cryopreserved in an ice-free state by rapid cooling to -100 degrees C in cryoprotectant (VS55), followed by vitrification to -120 degrees C. After cryopreservation, the metanephroi were stored at -135 degrees C for 48 hours. After storage the MN were rewarmed, resuspended in culture media, and their viability was assessed using the AlamarBlue assay and histology (light microscopy, TEM, and cryosubstitution). RESULTS: There was statistically no difference in embryonic kidney metabolic activity of either of the cryopreserved MN groups relative to the control untreated group. However, cryosubstitution demonstrated the presence of significant ice formation during controlled-rate freezing, yet in contrast the amount of ice was significantly reduced by vitrification. This was confirmed by TEM, where vacuolation of the cytoplasm of controlled-rate frozen metanephroi was observed, whereas vitrified metanephroi had little cytoplasmic disruption. However, vitrified metanephroi showed mitochondrial and nuclear injury at the cellular level. CONCLUSIONS: There is a need for long-term storage of organs to make MN transplantation a reality. This study demonstrates that standard freezing methods are unsuitable for this purpose. Vitrification yielded more promising results, but further development is required.

Ischaemic heart disease, cardiac surgery and heart/heart-lung transplantation reviewed from a haematological perspective.

Ischaemic heart disease, one of the major causes of death in the western world, seems to involve a complex interaction of haematological, biochemical, immunological, and physiological processes. Haematologically, the process involves alterations in the haemostatic mechanism as a result of elevations of certain clotting factors, particularly factor VII and fibrinogen, possibly as a result of increased fat consumption and smoking. Platelet hypersensitivity may also be related to immunological damage of the coronary endothelium and elevated fibrinogen levels. Cardiac surgery and heart transplantation remain the most effective methods for treatment of end-stage ischaemic heart disease. Surgical techniques are complex and necessitate the establishment of an extracorporeal blood circulation to bypass the functions of the heart and lungs, enabling the heart to be temporarily paralysed, and allowing surgery to be performed. Extracorporeal oxygenation and circulation of blood, and implantation of ventricular assist devices and artificial hearts, result in exposure of blood to foreign surfaces, leading to activation of the haemostatic mechanism and concomitant haemorrhagic/thrombotic complications. Heart and heart/lung transplantation require long-term regular monitoring of infection and rejection episodes in addition to control of bleeding complications sometimes experienced in the immediate post-operative period. Early identification of lymphoproliferative disorders which may arise as a result of excessive immunosuppression is also important. Implantation of artificial hearts and ventricular assist devices requires much more sophisticated haemostatic monitoring than routine cardiac surgery, in order to control the haemorrhagic/thrombotic complications so often associated with these procedures.

Automated haematology analysers: a four-way comparison.

Four automated haematology analysers--the Coulter S + IV, Coulter STKS, Sysmex NE8000, and Technicon H1--were evaluated for operational and quantitative differences. The measured blood count parameters (red cell, white cell and platelet counts, mean cell volume [MCV], haematocrit and haemoglobin) all compared well with the S + IV, although the MCV showed the greatest variation. Of the white cell differential parameters, neutrophils, lymphocytes and eosinophils correlated well with manually performed 400 cell differential counts. Mononuclear cell and monocyte counts generated by the S + IV and NE8000 (respectively) compared poorly with the manual method. The STKS, NE8000 and H1 gave an acceptable five cell population differential from samples stored in K2EDTA for up to 18 h, although the monocyte count from the NE8000 showed considerable variation during that period. All instruments were shown to operate efficiently in either primary or secondary operating mode, but the STKS and NE8000 were considerably faster than the H1, and easier to use in the automated mode.

Chondrosarcoma of spermatic cord.

A case of extraosseous chondrosarcoma arising from the spermatic cord is reported and the literature reviewed. Chondrosarcoma arising from nonosseous tissue is rare, and only a handful of cases have been reported. However, unlike chondrosarcoma of bone, extraosseous myxoid chondrosarcoma behaves in a less aggressive fashion making the distinction between the two entities prognostically significant.