Spontaneous hypoxaemia and right ventricular hypertrophy in fast growing broiler chickens reared at sea level

1. At 6 weeks of age, the time of most rapid body growth, fast growing broiler chickens showed more right ventricular hypertrophy than slower growing chickens. 2. The degree of right ventricular hypertrophy was directly related to blood haematocrit and indirectly related to arterial oxygen saturation (estimated in the chickens using an ear oximeter designed for man). 3. When oxygen saturation was estimated sequentially from 6 to 17 weeks of age, mean oxygenation improved with age, partly due to the death of the chickens with the worst saturations, but also because of an improvement in oxygenation of the survivors.     

The Chatt cycle and the mechanism of enzymic reduction of molecular nitrogen

 The Chatt Cycle is a hypothetical model for the mechanism of nitrogenase action at the atomic level and is based upon reactions of certain well-defined molybdenum compounds. The proton and electron-transfer chemistry of the cycle is reviewed, revised and extended. An explanation for general and obligatory hydrogen evolution by the nitrogenase system is advanced; this involves carboxylate acting as a tethered leaving group at the Mo centre and the formation of mono-, di- and tri-hydric intermediates. The chemical model is integrated with the biochemical model proposed by Lowe and Thorneley. Received and accepted: 21 August 1996