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Biomedical subjects

S Mercik

Publications and source records attributed to S Mercik.

3 recordsLinked to original sources

Stochastic origins of the long-range correlations of ionic current fluctuations in membrane channels.

An explicit stochastic representation of a stationary ionic current signal recorded from a single channel of a biological membrane is presented. In the framework of the proposed approach we show how the dichotomous time structure of the signal leads to the non-Markovian character of the channel current. The rescaled range Hurst and detrended fluctuation analyses confirm the theoretical result. To investigate the ionic current fluctuations we introduce the Orey index as a statistical method providing additional information on the properties of stochastic processes. In order to reveal any differences between the experimental and reconstructed signals, we apply also the statistical tests to the model-based simulations of the channel action.

Cell Membrane↗

Statistical analysis of ionic current fluctuations in membrane channels.

The statistical analysis of an ionic current signal recorded from a single channel of a biological membrane is presented. We find the main characteristics of the ionic current probability density, the closed- and open-state distributions, and the autocorrelation function of the current recordings by using procedures based on the kernel and tail estimators, the bootstrap methodology; and the Zipf plots. The results provide evidence for the non-Markovian character of the channel kinetics of the investigated data.

Animals↗

Technical considerations in the gas chromatographic analysis of desipramine.

Procedures are presented for minimizing variability in and interferences with the gas chromatographic determination of desipramine in plasms. Careful consideration of procedures for sample collection and storage, drug separation from matrix components, and chromatography appears to be a prerequisite for avoiding inaccurate and imprecise determinations of this antidepressant, especially at levels below 20 micrograms/l. Numerous pitfalls are examined and optimal conditions for obviating them are presented.

Blood Specimen Collection↗