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'.

Inhaled nitrous oxide (Entonox) as a short acting sedative during bone marrow examination

Bone marrow aspiration and biopsy is a procedure of central importance in the diagnosis of haematological disease and is one that can be safely performed in the outpatient clinic using only local anaesthesia. We evaluated the role of inhaled nitrous oxide (Entonox) as an adjuvant to local anaesthesia (LA) in patients requiring bone examination. We prospectively studied the role of Entonox in patients attending our outpatient department who required bone marrow examination. All patients received LA with injected 2% lignocaine but patients were then assigned to either LA alone or LA plus inhaled Entonox. Following the procedure patients were given a questionnaire and asked to score the discomfort associated with the procedure. Twenty-eight of 85 patients (33%) who received LA alone scored their pain as 3 (severe) compared with seven of 51 patients (14%) who received LA plus Entonox, P = 0.013. No adverse events were associated with Entonox use. Forty-three of the 51 patients who received Entonox stated that they would prefer to use this method of anaesthesia again. We conclude that inhaled Entonox is a useful adjuvant to local anaesthesia for patients undergoing bone marrow examination.

Cytomegalovirus-induced T-cell proliferation and the development of progressive multifocal leucoencephalopathy following bone marrow transplantation

Progressive multifocal leucoencephalopathy (PML) is a rare disorder characterized by progressive demyelination within the brain. It is usually fatal and occurs when there are defects in cell-mediated immunity. We report a case of PML which developed following allogeneic bone marrow transplantation. It was preceded by the development of a persistent polyclonal expansion of large granular lymphocytes (LGLs) which appeared to rise as a consequence of cytomegalovirus infection.

Effects of chronic administration of benfluorex to rats on the metabolism of corticosterone, glucose, triacylglycerols, glycerol and fatty acid

(1) Rats were fed on diets enriched with sucrose, beef tallow or corn oil and treated for 11-16 days with 50 mg of benfluorex per kg of body weight. By these times the growth rate and food intake were not significantly different from those of control rats. (2) Benfluorex approximately halved the concentration of circulating triacylglycerol in rats fed the beef tallow or sucrose diets. (3) It did not significantly alter the total lipoprotein lipase activity in diaphragm, heart and adipose tissue. (4) The clearance of triacylglycerols from chylomicrons exhibited two t 1/2 values of about 0.6 and 6.9 min in rats fed the beef tallow diet. Benfluorex did not significantly alter these values. (5) Benfluorex did not significantly alter the rate of appearance of triacylglycerol in the blood of rats injected with Triton WR 1339 to block triacylglycerol uptake. It did, however, decrease the rise in circulating glucose which presumably resulted from the stress of the procedure. (6) Benfluorex decreased the extent and duration of the rise in serum corticosterone when rats maintained on the corn oil diet were fed acutely with fructose. It also decreased the circulating concentrations of glycerol, triacylglycerol and glucose after fructose feeding. (7) Rats fed on the corn oil diet and then treated with benfluorex had lower concentrations of circulating glucose, triacylglycerol, glycerol and fatty acids after being injected with 2-deoxyglucose. (8) It is proposed that some of the long-term hypoglycaemic and hypotriglyceridaemic effects of benfluorex could be mediated indirectly through changes in endocrine balance, perhaps via the serotonergic system and in particular, by decreasing the effects of stress hormones relative to insulin. The implications of these findings are discussed in relation to controlling metabolism in stress conditions and for the management of obesity, diabetes and atherosclerosis.