Biomedical subjects
S Bradbury
Publications and source records attributed to S Bradbury.
Comparative study of automatic blood-gas analysers and their use in analysing arterial and capillary samples.
Three automatic blood-gas analysers were compared for ease of use; calibration; reproducibility and accuracy of results; maintenance; fault-finding; and use of expert technician time. Results obtained from arterial and capillary blood were compared with duplicate values obtained with a semi-automatic analyser controlled and calibrated with tonometered blood. No analyser was fully automatic, and all three needed maintenance by expert technicians. Difficulties were encountered when inexperienced operators used the machines. One automatic blood-gas analyser gave aberrant values for oxygen pressure (PO2) due to electrode dysfunction that was not indicated by the fault-finding system. A second analyser gave significantly lower values for blood pH than the standard machine. A comparison of pH, carbon dioxide pressure (PCO2), and PO2 measured in 40 simultaneous paired samples of arterial and arterialised capillary blood showed no significant difference for pH or PCO2, but the PO2 values were significantly lower in the capillary samples over the range studied. We conclude that all machines perform satisfactorily in terms of blood-gas analysis, but none may be regarded as fully automatic. Some degree of technical supervision is essential, as is proper training for all potential users.
Microscopical image analysis: problems and approaches.
This article reviews some of the problems which have been encountered in the application of automatic image analysis to problems in biology. Some of the questions involved in the actual formulation of such a problem for this approach are considered as well as the difficulties in the analysis due to lack of specific constrast in the image and to its complexity. Various practical methods which have been successful in overcoming these problems are outlined, and the question of the desirability of an opto-manual or semi-automatic system as opposed to a fully automatic version is considered.
A quantitative study of peripheral nerve fibres in the mouse following the administration of drugs. 1. Age changes in untreated CBA mice from 3 to 21 months of age.
This study is concerned with the quantification of changes which occur in peripheral nerves of normal mice from the onset of maturity to old age. The parameters chosen were total fibre area and axon area. Size distributions of these were expressed in the form of histograms. From the area data notional fibre and axon diameters were calculated, together with the thickness of the myelin sheath. The notional diameters were contrasted with the comparable myelin sheath thickness in the form of scatter diagrams. These results are intended to provide a reference scale for subsequent assessment of changes induced by drugs administered throughout life. The are in general accord with previous observations, but were obtained quickly, and with less margins of error, by using a Quantimet 720.