Surfactant uptake dynamics in mammalian cells elucidated with quantitative coherent anti-stokes Raman scattering microspectroscopy.

The mechanism of surfactant-induced cell lysis has been studied with quantitative coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The dynamics of surfactant molecules as well as intracellular biomolecules in living Chinese Hamster Lung (CHL) cells has been examined for a low surfactant concentration (0.01 w%). By using an isotope labeled surfactant having CD bonds, surfactant uptake dynamics in living cells has been traced in detail. The simultaneous CARS imaging of the cell itself and the internalized surfactant has shown that the surfactant molecules is first accumulated inside a CHL cell followed by a sudden leak of cytosolic components such as proteins to the outside of the cell. This finding indicates that surfactant uptake occurs prior to the cell lysis, contrary to what has been believed: surface adsorption of surfactant molecules has been thought to occur first with subsequent disruption of cell membranes. Quantitative CARS microspectroscopy enables us to determine the molecular concentration of the surfactant molecules accumulated in a cell. We have also investigated the effect of a drug, nocodazole, on the surfactant uptake dynamics. As a result of the inhibition of tubulin polymerization by nocodazole, the surfactant uptake rate is significantly lowered. This fact suggests that intracellular membrane trafficking contributes to the surfactant uptake mechanism.

[Stress granules in the cells with intact and discrupted microtubules: analysis with new algorithm of image processing].

Stress granules--temporary RNP structures that are formed in cells under stress. They are studied mainly by means of fluorescence microscopy with the quantitative analysis of cell images. We have developed a new algorithm for automatic detection of stress granules in the cytoplasm of cultured animal cells having non-uniform cytoplasmic background. Using this approach, we have found that visible stress granules are formed in cells as "all or nothing", and their number in cells is rather constant. We also show that disruption of cellular microtubules lead to a decrease in the average size of stress granules and an increase in their number in the cell.

Different thresholds of MPF inactivation are responsible for controlling different mitotic events in mammalian cell division.

We present evidence for a paradigm that, during cell division, the decreasing activity of MPF acts as a master signal, which utilizes different thresholds to control the initiation of different mitotic events. The key temporal control here is the degradation of cyclin B1. Using single cell analysis, we measured the kinetics of cyclin B1 degradation and determined quantitatively the thresholds of cyclin B1 level for different mitotic events within a HeLa cell. These observed thresholds were: 1.36 +/- 0.49 microM (for chromosome separation), 0.75 +/- 0.08 microM (for cytokinesis) and 0.54 +/- 0.16 microM (for nuclear reassembly). By comparison, the average concentration of endogenous cyclin B1 within a prometaphase cell was found to be 2.92 +/- 1.7 microM. We suggest that the decreasing order of these thresholds plays an important role in triggering the initiation of successive mitotic events in cell division.

[Experimental chemotherapy of alveolar hydatid disease. 12. The efficacy of drug forms of mebendazole and nocodazole with high bioavailability]. / Eksperimental'naia khimioterapiia al'veokokkoza. Soobshchenie 12. Effektivnost' lekarstvennykh form mebendazola i nokodazola s povyshennoi biostupnost'iu.

New formulations have been designed to increase the efficacy and bioavailability of the oral drugs mebendazole and nocodazole and were tested in CBA mice. A considerable increase in efficacy was established for a solid disperse formulation of certain composition with a relatively lower toxicity than in aqueous suspensions of the drugs.