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Biomedical subjects

J Formánek

Publications and source records attributed to J Formánek.

At least 19 recordsLinked to original sources
PubMed1990

Detection and interpolation of outliers in biosignals.

Detection of outliers in recorded biosignals and their interpolation is described. The detection of outliers is based on the simple rule of 3 sigma. The subsequent interpolation is performed according to the method proposed by Brubacher and Wilson for autoregressive processes. The output of the suggested procedure can be treated by standard programs of statistical analysis as long as the influence of outliers is eliminated. The program in Fortran IV developed in the Institute of Hygiene and Epidemiology, Prague, performs automatically the detection of outliers in an input signal and their replacement by means of the proposed interpolation method.

Animals↗
PubMed1988

EEG as a neurotoxicological indicator.

In living organisms both chemical agents and physical factors [16] may produce neurophysiological change that affects EEG activity. EEG signals are very suitable for non-invasive measurement of CNS reactions, but quite complicated equipment is necessary for measurement and analysis. We have implemented a system that permits the study of EEG changes both in time and frequency domains using broad-band analysis or fast Fourier transformation (FFT). Experimental animals were influenced by high doses of toxic agents (CO, CS2, barbiturates, pesticides), drugs and both non-ionizing and ionizing radiation. The EEG changes reflecting the influencing factor, respectively its quantity may be divided into several classes: (1) appearance of new activities; (2) disappearance of some activities; (3) increase of amplitudes, respectively spectral power densities (SPD) in certain frequencies; and (4) decrease of amplitudes, respectively SPD in certain frequencies. All changes are related to the controls, i.e. to the relatively normal state of CNS. Furthermore it is possible to investigate the temporal dynamics of these changes. Physiological concordance of these findings is sometimes possible from clinical analogues, but in other cases is unknown and considerable effort will be necessary to elucidate these correlates. Anyhow in some toxic substances, the EEG may be quite insensitive as an indicator of neurotoxicity. The best way to solve these problems is to collect sufficient experimental data for complex analysis. Although few relevant data are currently available, temporal and frequency domain measures of EEG activity appear to have promise as neurotoxicity indicators.

Animals↗
PubMed1981

Analysis of the time series of the EEG frequency spectra and of EEG spectral power densities.

Some examples of the use of the principal component model for the economic description of the structure of the multiple time series and for the data reduction in the quantitative EEG studies are presented. The broad-band EEG frequency spectra were measured with the use of an electronic system designed by J. Dvorák. The EEG spectral power densities were computed via the discrete Fourier Transform (namely FFT) algorithm. The estimated two or three first principal components account for the major part of the total variance of individual EEG variables: The results hold for the used elementary epoch of measurement, i.e. 5 sec. - With the use of the algorithms and FORTRAN IV programs developed by J. Andĕl, T. Cipra and L. Tomásek a data reduction by a factor of 1:2000 can be achieved without any substantial loss of biological information. - The described methods help to obtain a better insight into the structure of the data and represent a powerful tool for data reduction at least in a certain class of experimental EEG studies (experimental toxicology, pharmacology, experimental neurology).

Animals↗
PubMed1976

Surveillance of pertussis in the CSSR. IV. Immunological surveys of antibodies to pertussis and parapertussis in the Bohemian regions and in Slovakia in 1958 - 1971.

A comparison of the results of repeated immunological surveys with the notification of morbidity and mortality to pertussis and parapertussis revealed direct dependence and simultaneously confirmed the effectiveness of Czechoslovak vaccine. Immunological surveys should be continued in spite of the fact that morbidity of pertussis is low at present, because immunological surveys may lead to timely detection of shortcomings in the quality of vaccination and vaccine. The results after 14 years of systematic vaccination and revaccination and consequent follow-up to the state of immunity in the population and of other factors in the pertussis surveillance programme rank among the other achievements of epidemiology and hygiene in Czechoslovak health services. Contemporary immunological surveys show that the state of immunity in Czechoslovak child population is such as to exclude the occurrence of pertussis in epidemics in the nearest future. The situation is different in parapertussis where epidemic incidence is still possible and where epidemics regularly occur in children of prae-school age.

Adolescent↗
PubMed1975

[Penicillinase of Staphylococci isolated from milk and dairy products].

Examinations were performed in 173 strains of Staphylococcus aureus isolated from milk and dairy products. Of this number, 143 strains were resistant and 30 sensitive to penicillin. All the resistant strains produced penicillinase. Penicillinase production was demonstrated also in vivo by a test on white mice.

Animals↗