In vivo suppression of phytochrome aggregation by the GroE chaperonins in Escherichia coli

When expressed in Escherichia coli, a truncated form of phytochrome (oat PHYA AP3 residues 464-1129) self associates to form a series of products ranging in size from monomers to aggregates of greater than 20 subunits. When these same phytochrome sequences are coexpressed with the chaperonins GroEL and GroES, the truncated phytochrome migrates as a native-like dimer in size exclusion chromatography and no higher-order aggregates were detected. GroEL and GroES inhibition of phytochrome aggregation in E. coli presumably occurs via the suppression of folding pathways leading to incorrectly folded phytochrome.     

Guidelines on appropriate indications for upper gastrointestinal endoscopy. Working Party of the Joint Committee of the Royal College of Physicians of London,Royal College of Surgeons of England,Royal College of Anaesthetists,Association of Surgeons,the British Society of Gastroenterology,and the Thoracic Society of Great Britain.

Upper gastrointestinal endoscopy is a valuable diagnostic tool, but for an endoscopy service to be effective it is essential that it is not overloaded with inappropriately referred patients. A joint working party in Britain has considered the available literature on indications for endoscopy, assessed standard practice through a questionnaire, and audited randomly selected cases using an independent panel of experts and an American database system. They used these data to produce guidelines on the appropriate and inappropriate indications for referral for endoscopy, although they emphasise that under certain circumstances there may be reasons to deviate from the advice given. The need for endoscopy is most difficult to judge in patients with dyspepsia, and this aspect is discussed in detail. Early endoscopy will often prove more cost effective than delaying until the indications are clearer.