Biomedical subjects
Publications and source records attributed to B Colla.
The efficacy of the dacryocystorhinostomy (DRC) procedures, as performed at the University Hospital of Louvain, has been evaluated by means of a retrospective study on 165 consecutive patients. The overall success rate was 94%.
In children aged 3 months or older lacrimal probing was performed to cure nasolacrimal duct obstructions. In 56 cases where this procedure failed a silicone tube was inserted. The results were favourable in 47 cases. Children with facial malformations and those with a narrow nasolacrimal duct however proved to be poor candidates for silicone tube insertion.
A computer method analysing Frank VCG recorded on rest and on exertion, is presented. Electrical noises due to exercise are eliminated by averaging 8 complexes. The pattern-recognition of every wave is carried out by analysing a particular function obtained by translating the X, Y, Z leads on the line joining the T-P, P-Q, ST and subsequent T-P segment. The following parameters are evaluated: maximal and mean vector, linear, areolar and tangential (our original method) spatial velocity, half-area vector, area described by the spatial vector and oriented according to X, Y, Z polarity.
When characterization of the specificity of an antiserum for radioimmunoassay (RIA) is performed by the conventional method, the conditions under which interference occurs are not respected because of the lack of specific antigen. We have studied the behavior of antisera reproducing the real environment existing in unknown samples, in which antigen, interferent and tracer complete simultaneously. A testosterone (T) antiserum and a 5 alpha-dihydrotestosterone (D) anti serum were characterized by setting up two distinct hapten recovery tests in the presence of both the hapten and the crossreactant added to steroid-free serum in various concentrations in order to reproduce multiple concentration ratios. These samples, together with the standard curves samples (prepared by 'spiking' steroid-free serum with known concentrations of T or D) were extracted and subjected to T-RIA and D-RIA without purification. The results have shown that the interferent-induced incremental ratio is a linear function of the ratio of the levels of cross-reactant and hapten via a proportionality factor inversely correlated to the antiserum specificity. By means of this function, the overestimated T and D levels found in samples after 'extraction only' have been corrected and the resulting values have shown acceptable correlation with the corresponding levels determined after column chromatography.
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A programme of on-line automated analysis of ECG exercise graphs relative to the CB5 derivation is described. The various operations may be subdivided into the following phases: 1) performance; 2) mean complex; 3) identification; 4) calculation and print-out of parameters; 5) filing. Automatic analysis of exercise ECG's eliminating artifacts present in graphs and obtaining parameters that are not respectively assessable, facilitates the development of rigorously objective diagnostic guidelines. The filing of indices on magnetic tape opens the way to subsequent statistical analysis of extreme usefulness in testing extensive populations.
The use of computers in the exercise of electrocardiography is considered. The problems related to this use concern the choice of leads, the filtration of the signal, the recognition of characteristic segments of ECG, the calculation of various indexes and their statistical evaluation for diagnostic purposes. The authors use a bipolar derivation filtered by averaging and digital filters. The characteristic points of ECG are recognized by the analysis of the curvature. The Tchebycheff coefficients of the S-T tract are evaluated; they appeared to be a very good means for judging positive and negative cases.
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