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Biomedical subjects

E O Wandl

Publications and source records attributed to E O Wandl.

4 recordsLinked to original sources
PubMed1990

Use of the micronucleus assay for the selective detection of radiosensitivity in BUdR-unincorporated cells after pulse-labelling of exponentially growing tumour cells.

To determine the radiosensitivity of non-S-phase tumour cells in vitro, survival curves of SCC VII tumour cells were obtained after a short block with hydroxyurea. Dose-response curves of micronucleus (MN) frequency appearing in non-S-phase cells were also determined by excluding S-phase cells with immunofluorescence staining to 5-bromo-2'-deoxyuridine (BUdR). Both the dose-response curves of MN frequency and survival curves were analysed by a linear-quadratic model (surviving fraction = exp (-alpha D-beta D2), MN frequency = aD+bD2+c). A good correlation between the alpha/beta and alpha/beta ratios was observed. In both BUdR-unincorporated and asynchronous cell cultures, the regression lines between the surviving fraction and micronucleus frequency were statistically identical. Therefore, it was shown that cell survival curves, which cannot be obtained directly by the routine colony-formation technique, can be calculated using the micronucleus frequency and the regression line in asynchronous cell cultures. Therefore, it should be possible to detect the response to irradiation of quiescent cells in tumours using the immunofluorescence staining to BUdR and the MN frequency assay.

Bromodeoxyuridine↗
PubMed1990

[Oxygen consumption during photodynamic therapy in vitro].

The consumption of dissolved molecular oxygen was measured during photodynamic therapy in vitro. Aqueous solutions of hematoporphyrin derivative (HpD) containing different concentrations of serum or numbers of cells were prepared. Decrease in oxygen in the solution and cell suspensions was monitored during light-irradiation (at a wavelength of 610 to 640 nm). The rate of oxygen consumption increased with increasing concentrations of HpD, serum levels or numbers of cells. Upon repeated irradiation of the same solutions (after restitution of the initial pO2 of 100 mm Hg), the rate of oxygen consumption decreased indicating a disaggregation process of HpD. The rate of oxygen content of the solutions decreased independently of the actual oxygen partial pressure. Even at a low pO2 below 10 mm Hg, oxygen consumption was unimpeded until the solutions were free of oxygen. No O2-consumption was noted in aqueous solutions of HpD (up to 40 g/ml) without serum or cells during irradiation.

Cells, Cultured↗
PubMed1990

[Chemo- and radiosensitivity testing of tumor tissue cultured in vitro. Development of a fiber culture system for cell harvesting].

Chemo- and radiosensitivity-testing of tumour cells should be performed in vitro under in vivo-like conditions. One problem is to grow cells to tissue-like cell densities in vitro. A hollow fiber reactor was prepared for cell growth to high densities. In order to obtain cells during and after sensitivity testing for quantitating cell damage, a harvesting fiber system was developed which can be inserted in the nutritional hollow fiber system. These hollow fibers have a diameter of 300 microns and a wall thickness of 10 microns. Small holes between 10 and 100 microns can be cut into the fibers for cell harvesting by electric sparks. Up to 60 holes per mm fiber length can be produced.

Cytological Techniques↗