Haemodialysis and transplantation in Wegener's granulomatosis.

Two men with Wegener''s disease began immunosuppressive treatment during severe renal insufficiency. Despite an initial temporary remission new lesions appeared and renal failure progressed. Haemodialysis was started, cytotoxic drugs were stopped, and steroid dosage was reduced. All extrarenal manifestations of the disease remitted, however, suggesting a favourable effect of either the immunosuppression induced by terminal renal failure or the haemodialysis itself. Renal transplantation was then undertaken in both patients. Thirteen and 55 months after the operations respectively renal function was satisfactory and no signs of reactivation of Wegener''s disease had appeared. These results show that whatever the activity of Wegener''s disease and its initial response to immunosuppressive agents, dialysis and transplantation are fully warranted once irreversible renal failure is established.     

Longevity of men capable of prolonged vigorous physical exercise: a 32 year follow up of 2259 participants in the Dutch eleven cities ice skating tour.

OBJECTIVE--To compare the long term survival of a group of athletes taking prolonged vigorous physical exercise to that of the general population. DESIGN--Follow up of a cohort of participants in the Dutch eleven cities ice skating tour (a race and recreational tour) over a distance of 200 kilometers. SETTING--Data on participation from the organising committee and data on mortality from all municipalities in The Netherlands. SUBJECTS--2259 Male athletes. MAIN OUTCOME MEASURES--Comparison of all cause mortality in male participants in the tour with that in the general population of The Netherlands. RESULTS--The standardised mortality ratio for all participants during 32 years of follow up was 0.76 (95% confidence interval 0.68 to 0.85), and 0.90 (0.48 to 1.44) for participants in the race, and 0.72 (0.60 to 0.86) for participants in the recreational tour who finished within the time limit. CONCLUSIONS--The capacity for prolonged and vigorous physical exercise, particularly if the exercise is recreational, is a strong indicator of longevity.     

Electrified bioreactors: the next power-up for biometallurgical wastewater treatment

Over the past decades, biological treatment of metallurgical wastewaters has become commonplace. Passive systems require intensive land use due to their slow treatment rates, do not recover embedded resources and are poorly controllable. Active systems however require the addition of chemicals, increasing operational costs and possibly negatively affecting safety and the environment. Electrification of biological systems can reduce the use of chemicals, operational costs, surface footprint and environmental impact when compared to passive and active technologies whilst increasing the recovery of resources and the extraction of products. Electrification of low rate applications has resulted in the development of bioelectrochemical systems (BES), but electrification of high rate systems has been lagging behind due to the limited mass transfer, electron transfer and biomass density in BES. We postulate that for high rate applications, the electrification of bioreactors, for example, through the use of electrolyzers, may herald a new generation of electrified biological systems (EBS). In this review, we evaluate the latest trends in the field of biometallurgical and microbial-electrochemical wastewater treatment and discuss the advantages and challenges of these existing treatment technologies. We advocate for future research to focus on the development of electrified bioreactors, exploring the boundaries and limitations of these systems, and their validity upon treating industrial wastewaters.     

How can we possibly resolve the planet's nitrogen dilemma?

Nitrogen is the most crucial element in the production of nutritious feeds and foods. The production of reactive nitrogen by means of fossil fuel has thus far been able to guarantee the protein supply for the world population. Yet, the production and massive use of fertilizer nitrogen constitute a major threat in terms of environmental health and sustainability. It is crucial to promote consumer acceptance and awareness towards proteins produced by highly effective microorganisms, and their potential to replace proteins obtained with poor nitrogen efficiencies from plants and animals. The fact that reactive fertilizer nitrogen, produced by the Haber Bosch process, consumes a significant amount of fossil fuel worldwide is of concern. Moreover, recently, the prices of fossil fuels have increased the cost of reactive nitrogen by a factor of 3 to 5 times, while international policies are fostering the transition towards a more sustainable agro-ecology by reducing mineral fertilizers inputs and increasing organic farming. The combination of these pressures and challenges opens opportunities to use the reactive nitrogen nutrient more carefully. Time has come to effectively recover used nitrogen from secondary resources and to upgrade it to a legal status of fertilizer. Organic nitrogen is a slow-release fertilizer, it has a factor of 2.5 or higher economic value per unit nitrogen as fertilizer and thus adequate technologies to produce it, for instance by implementing photobiological processes, are promising. Finally, it appears wise to start the integration in our overall feed and food supply chains of the exceptional potential of biological nitrogen fixation. Nitrogen produced by the nitrogenase enzyme, either in the soil or in novel biotechnology reactor systems, deserves to have a ‘renaissance’ in the context of planetary governance in general and the increasing number of people who desire to be fed in a sustainable way in particular.     

Assessing the potential for up-cycling recovered resources from anaerobic digestion through microbial protein production

Anaerobic digesters produce biogas, a mixture of predominantly CH₄ and CO₂, which is typically incinerated to recover electrical and/or thermal energy. In a context of circular economy, the CH₄ and CO₂ could be used as chemical feedstock in combination with ammonium from the digestate. Their combination into protein-rich bacterial, used as animal feed additive, could contribute to the ever growing global demand for nutritive protein sources and improve the overall nitrogen efficiency of the current agro- feed/food chain. In this concept, renewable CH₄ and H₂ can serve as carbon-neutral energy sources for the production of protein-rich cellular biomass, while assimilating and upgrading recovered ammonia from the digestate. This study evaluated the potential of producing sustainable high-quality protein additives in a decentralized way through coupling anaerobic digestion and microbial protein production using methanotrophic and hydrogenotrophic bacteria in an on-farm bioreactor. We show that a practical case digester handling liquid piggery manure, of which the energy content is supplemented for 30% with co-substrates, provides sufficient biogas to allow the subsequent microbial protein as feed production for about 37% of the number of pigs from which the manure was derived. Overall, producing microbial protein on the farm from available methane and ammonia liberated by anaerobic digesters treating manure appears economically and technically feasible within the current range of market prices existing for high-quality protein. The case of producing biomethane for grid injection and upgrading the CO₂ with electrolytic hydrogen to microbial protein by means of hydrogen-oxidizing bacteria was also examined but found less attractive at the current production prices of renewable hydrogen. Our calculations show that this route is only of commercial interest if the protein value equals the value of high-value protein additives like fishmeal and if the avoided costs for nutrient removal from the digestate are taken into consideration.