, the tDepartment of Pathology, The Royal Hospital, Wolverhampton, and the tSchool ofPharmacy, Leicester Polytechnic, Leicester SUMMARY Glycated haemoglobin and glycated protein (fructosamine) and blood glucose concentrations were measured in blood samples collected from 75 patients at necropsy. Estimation of blood glucose was a poor indicator of glycaemia before death. Measurement of glycated haemoglobin by affinity chromatography distinguished non-diabetic patients from diabetic patients. The distinction was not as clear cut when HbA, was estimated using electroendosmosis. Seven patients, who at necropsy had no known history ofdiabetes, had glycated haemoglobin concentrations in the diabetic range. Two of these patients were found to be diabetic, and diabetes had been suspected at some time in another three patients.It is concluded that measurement of glycated haemoglobin or HbA, in necropsy specimens is a valuable tool for assessing glycaemic control in known diabetic patients, and may be useful in diagnosing previously unsuspected diabetes.
Biotyping, antibiograms, bacteriophage typing, plasmid profile analysis and SDS-PAGE protein profiles were used to determine the relatedness of 44 Staphylococcus epidermidis and four S. haemolyticus isolates from 14 patients. A selection of these were further characterised by ribotyping. Biotyping classified the isolates into three major groups but was considered a poor strain marker. Although antibiograms classified the S. epidermidis isolates into 20 groups, some changes in the susceptibility patterns of related isolates from a single patient were demonstrated. Bacteriophage typing was the least discriminatory of the methods used. SDS-PAGE gave highly related patterns for the majority of S. epidermidis isolates. Plasmid profile analysis and ribotyping, with a minimum of two restriction endonucleases, were the most discriminatory methods for typing S. epidermidis. Nonetheless, some isolates from the same patient -probably representing a single strain -varied in plasmid profile indicating plasmid instability. One of six related isolates from a single patient lacked two bands from the ribotyping pattern of the other isolates. Although no single method proved entirely satisfactory on all occasions, the combination of typing methods was sufficient to provide evidence of the relatedness of S. epidermidis isolates from individual patients.
I n t ro du c ti onThe coagulase-negative staphylococci (CNS), particularly Staphvlococcus epidermidis, are recognised as important nosocomial pathogens, especially in patients with prosthetic implant devices and immunocompromised patients [l]. Recent studies have also demonstrated CNS to be the most common blood culture isolates in neonatal intensive care units [2]. However, strains of S. epidermidis are also the most prevalent species on human skin surfaces, representing up to 90% of all staphylococci recovered [3]. Weinstein et al.[4], using both clinical and microbiological data obtained from a large series of blood culture isolates, were able to differentiate true pathogens from contaminants and considered 94% of the CNS to be clinically insignificant. Therefore, the isolation of CNS from blood cultures raises important questions both clinically and for the microbiology laboratory as to whether or not there is true clinical infection. Other species of CNS, especially S. haemolyticus, may also Isolates of CNS can be readily identified to species level in diagnostic laboratories and it is rarely considered necessary to confirm the relatedness of uncommonly isolated species. However, repeated isolates of the ubiquitous S. epidermidis and the increasingly important S. haernolyticus from individual patients necessitate typing to confirm rapidly and reliably their relatedness. This is important not only to identify nosocomial outbreaks but also to distinguish true infection, represented by repeated isolation of the same strain, from contamination, indicated by the isolation of different strains. In certain patient categories it is also important to distinguish relapse of infection w...
The distinction between organic chemistry and biochemistry is very unclear; most people regard the former as merging into the latter. For this reason, and for reasons of student interest and future employment, very many organic chemistry courses contain studies on biochemical processes including metabolic pathways, the associated reaction mechanisms, and relevant techniques.One of the main aims of the simple experiment described here is to illustrate the crucially important point that radioisotopes can be used to follow metabolic pathways and gain vital information on their nature and operation. The synthesis of protein is one of the most fundamental and interesting of biological processes and obviously it is desirable to be able to demonstrate it, and, if possible, to examine some of the factors affecting it. However, while experiments can be devised involving isolated ribosomes, mRNA, and so on, the lability of these materials and the time required for their preparation are awkward. The cost of some essential chemical components for such experiments can also be off-putting.
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