[Erytrocyte membrane change due to the chemical treatment studied with atomic force microscopy]. / Zastosowanie mikroskopii sil atomowych do badan zmian w blonie erytrocytów wywolanych czynnikami chemicznymi.

The influence of some selected pharmacological compounds on the structure of human erythrocytes (red blood cells, RBCs) has been studied by means of an atomic force microscopy (AFM). The imaging has been done both in the air environment on the fixed cells, and in the liquid (physiological conditions). It was shown that RBCs are very sensitive to osmotic changes in the solution. Increased NaCl concentration in the solution to a value higher than 0.9% leads to the characteristic changes of the erythrocyte from a discoid-like shape to a very irregular one, the so-called "echinocyte", with a lot of ledges. After exposition on nifedipin the modification of the erythrocyte surface morphology was observed. Based on the contact and non-contact AFMs study the consecutive stages of RBCs surface modification were observed. Scanning electron microscopy pictures of erythrocytes were presented for comparison.

[Does daily hemodialysis influence urea kinetic modeling (UKM) coefficients?--Preliminary report]. / Czy hemodializa codzienna wplywa na zmiane wspólczynników modelowania kinetycznego dializy?--Doniesienie wstepne.

Large number of data shows beneficial effects of implementing daily hemodialysis (DH) upon the outcome in patients dialysed previously in 3 times a week hemodialysis (3H) schedule. The mechanisms responsible for this phenomenon are still unclear, despite the time of low-flux DH sessions is shortened almost by half. Evaluation of the effect of doubling the number of hemodialyses per week upon so called cellular clearance (intercompartmental diffusion coefficient, Kc) computed in 2 pool-model was main aim of this study. 6 chronically dialysed patients (previously 3x per week) were subjected to DH. Based upon output data from UKM and weekly KT/V, the time for each DH session was computed, with no change in Kd (dialyser clearance). Kc was estimated from double-pool volume variable model equations and rebound. By the use of almost similar dialyser clearances in 16 conventional and 29 DH modeling sessions, estimated Kc values had been found non significantly higher in DH: (323.16; S.D. 187.86 vs. 268.80; S.D. 104.09 ml/min; p=0,68). Mean ultrafiltration/pre-dialysis body weight ratio (UFR/BW1) was 4,97 (S.D. 2.27)% in conventional hemodialysis and 3.66 (S.D. 1.46)% in DH. Mean dialysis index Kt/V values had decreased in DH (0.79; S.D. 0.17, vs. 1,34 (S.D. 0.26). Mean UFR/W1 ratio correlated negatively with Kc either in conventional or in DH (r=-0.653; p = 0.006 and r=-0.552; p=0.0036, respectively). Statistically significant negative correlation between Kt/V and Kc was found only in DH subjects (r=-0.466, p =0.010). The authors concluded, that increased Kc observed in patients subjected to DH may be responsible for better dialysis efficacy in patients switched into this treatment modality.

[New measurement techniques in biology and medicine: atomic force microscopy (part III)]. / Nowe techniki pomiarowe w biologii i medycynie: mikroskopia sit atomowych (czesc III).

Biological samples can be investigated with atomic force microscopy (AFM) in either of two imaging modes: contact mode or tapping mode. Applications of fluid tapping mode AFM in biology and medical sciences are constantly growing and the data obtained with this technique are improving, especially in terms of resolution. Even dynamic processes can be observed almost as they would occur in vivo. AFM is a proven imaging technique that has recently gained attention in biomaterials due to its ability to analyze surface properties, non-destructively at nanometer-level resolution in ambient air or in fluid environments.

[New measurement technics in biology and medicine: atomic force microscopy (part II)]. / Nowe techniki pomiarowe w biologii i medycynie: mikroskopia sil atomowych. (Czesc II).

At present, there are a lot of biological and medical research fields, where atomic force microscopy (AFM) is being successfully used. AFM has contributed to research in the investigation of DNA, RNA structure, nucleic acid--protein complexes, chromosomes, ligand-receptor binding, cell membranes, proteins, lipids, carbohydrates, living cells (yeasts, bacteria, neurons, erythrocytes, endothelial cells); it enables to monitor drug interactions with cells and tissues, to visualize changes in protein molecular structure and crystal growth. Unlike electron microscopes, samples do not need to be stained, coated or frozen. Recent work indicates that, in the near future, AFM may be employed in ultra-sensitive immunoassay detection without any kind of labeling for both qualitative and quantitative work. AFM is more than a surface--imaging tool in that force measurements can be used to probe the physical properties of the specimen, such as molecular interactions, surface hydrophobicity, surface charges, and mechanical properties.

[The new measurement technics in biology and medicine--atomic force microscopy]. / Nowe techniki pomiarowe w biologii i medycynie: mikroskopia sil atomowych (czesc I).

Scanning probe microscopy (SPM) has recently become the most dynamically developing technique employed in research investigations. Atomic force microscopy (AFM) that uses a digitally-controlled scanner and a cantilever system with a measurement tip shaped as a cone with the apex radius of 2-50 nm and the application force of 10(-10) N, as well as a system of recording detectors, has allowed for identification of numerous biological structures in a nanometer scale. The paper presents a review of measurement methods that employ the atomic force microscopy and are being used in medicine and biology, along with major achievements accomplished owing to this technique by various investigators, including the authors themselves.