Intra-operative anaesthetic management of older patients undergoing liver surgery.

Older patients represent a growing proportion of the general surgical caseload. This includes those undergoing liver resection, with figures rising faster than the rate of population ageing. The physiology of ageing leads to changes in all body systems which may render the provision of safe anaesthesia more challenging than in younger patients. Anaesthesia for liver surgery has specific principles, largely aimed at reducing venous bleeding from the liver, and those related to complex major surgery. This review explores the principles of anaesthesia for liver resection and describes how they may require modification in the older patient. The traditional approach of low central venous pressure anaesthesia in order to reduce bleeding may need to be altered in the presence of a cardiovascular system less able to tolerate hypotension and hypoperfusion. These changes in physiology should also lower the threshold for invasive monitoring. The provision of effective analgesia perioperatively should be tailored to minimise the surgical stress response and opiate use. Careful consideration of general principles of intra-operative care for older patients, such as positioning, drug dosing, avoidance of excessively deep anaesthesia, and maintenance of normothermia are also important given the prolonged, complex nature of liver surgery. This individualised approach, with careful attention to changes in physiology allows liver resections to be undertaken in older patients without increases in mortality.

Raising yield potential in wheat.

Recent advances in crop research have the potential to accelerate genetic gains in wheat, especially if co-ordinated with a breeding perspective. For example, improving photosynthesis by exploiting natural variation in Rubisco's catalytic rate or adopting C(4) metabolism could raise the baseline for yield potential by 50% or more. However, spike fertility must also be improved to permit full utilization of photosynthetic capacity throughout the crop life cycle and this has several components. While larger radiation use efficiency will increase the total assimilates available for spike growth, thereby increasing the potential for grain number, an optimized phenological pattern will permit the maximum partitioning of the available assimilates to the spikes. Evidence for underutilized photosynthetic capacity during grain filling in elite material suggests unnecessary floret abortion. Therefore, a better understanding of its physiological and genetic basis, including possible signalling in response to photoperiod or growth-limiting resources, may permit floret abortion to be minimized for a more optimal source:sink balance. However, trade-offs in terms of the partitioning of assimilates to competing sinks during spike growth, to improve root anchorage and stem strength, may be necessary to prevent yield losses as a result of lodging. Breeding technologies that can be used to complement conventional approaches include wide crossing with members of the Triticeae tribe to broaden the wheat genepool, and physiological and molecular breeding strategically to combine complementary traits and to identify elite progeny more efficiently.

Genotypic differences in deep water extraction associated with drought tolerance in wheat.

The ability of roots to extract soil moisture is critical for maintaining yields during drought. However, the extent of genotypic variation for rooting depth and drought tolerance in Northern European wheat (Triticum aestivum L.) germplasm is not known. The objectives of this study were to measure genotypic differences in root activity, test relationships between water use and yield, examine trade-offs between yield potential and investment of biomass in deep roots, and identify genotypes that contrast in deep root activity. A diverse set of 21 wheat genotypes was evaluated under irrigated and managed drought conditions in the field. Root activity was inferred from patterns of water extraction from the soil profile. Genotypes were equally capable of exploiting soil moisture in the upper layers, but there were significant genotypic differences in rates of water uptake after anthesis in deeper soil layers. For example, across the three years of the study, the variety Xi19 showed consistently deeper root activity than the variety Spark; Xi19 also showed greater drought tolerance than Spark. There were positive correlations between water extraction from depth and droughted yields and drought tolerance, but correlations between deep water use and yield potential were not significant or only weakly negative. With appropriate screening tools, selection for genotypes that can better mine deep soil water should improve yield stability in variable rainfall environments.

Multiple large infected scrotal sebaceous cysts masking Fournier's gangrene in a 32-year-old man.

Extensive large sebaceous cysts on the scotum are rare and present a problem only when infected or when cosmesis is deemed unacceptable by the patient. Fournier's gangrene is an infective condition with a high death rate. We describe a case of Fournier's gangrene in a patient masked by multiple large infected scrotal sebaceous cysts. A 32-year-old man with a history of alcohol dependency, cirrhosis and multiple scrotal sebaceous cysts presented with acute scrotal pain and erythema. Necrosis of the area became evident within 12 h of his admission and an emergency surgical debridement was performed. The wound was left open to heal via secondary intention over 4 weeks without complication. Fournier's gangrene is a rapidly progressive condition and early surgical debridement is crucial to achieve satisfactory outcomes. In this case, prompt intervention allowed a large scrotal defect to heal without the need for skin grafting.