Enno Rodegerdts

In Vitro Evaluation of Teratogenic Effects by Time‐Varying MR Gradient Fields on Fetal Human Fibroblasts

The purpose of this study was to evaluate the influence on fetal cell growth in vitro of rapidly changing magnetic gradient fields such as those produced by the gradient coils of a typical magnetic resonance (MR) imager. The static magnetic field and the radiofrequency pulses were disabled during all measurements. Human fetal fibroblasts were placed within a specially designed MR‐compatible incubation system inside the magnet. Trapezoid‐shaped waveforms of 500 and 75 Hz base frequency and an amplitude of 2 mT were applied for 2–24 hours. Proliferation of the cells was monitored for 3 weeks after exposure. Cell cycle analysis was performed until 24 hours after exposure to detect alterations in cell division. Tests were performed under two different conditions of growth to detect increased as well as decreased proliferation effects. None of these tests showed differences in proliferation and cell cycle distribution between exposed and nonexposed cells. J. Magn. Reson. Imaging 2000;12:150–156.

Detection of DNA double-strand breaks using γh2AX after MRI exposure at 3 Tesla: An in vitro study

To evaluate the effects of the static magnetic field and typical imaging sequences of a high‐field magnetic resonance scanner (3 Tesla) on the induction of double‐strand breaks (DSBs) in two different human cell lines.

In vitro evaluation of magnetic resonance imaging at 3.0 tesla on clonogenic ability, proliferation, and cell cycle in human embryonic lung fibroblasts.

Objectives:We investigated the influence of magnetic resonance (MR) at 3.0 T on clonogenic ability, proliferation, and cell cycle in an embryonic human cell line. Materials and Methods:Cells (human lung fibroblasts Hel 299) were exposed to the static magnetic field (3.0 T) of a magnetic resonance imager (MRI) and to a turbo spin echo sequence at 3.0 T within clinical limitations (specific absorption rate 0.92 W/kg). A special MR-compatible incubation system was used. A control group (sham-exposed) and a MRI group (exposed) were set up. We investigated 3 biologic endpoints: colony forming, cell cycle, and proliferation ability. The exposure time was 2 hours in each experiment. Results:In the statistical analysis, none of these tests showed relevant differences between the exposed and sham-exposed group. Conclusions:No influences of the static field alone as well as a turbo spin echo sequence at 3.0 T on clonogenic ability, proliferation, or cell cycle in eugenic human lung fibroblasts were found.

Biological effects of ionizing radiation on human blood compounds ex vivo

Purpose: Blood compounds are irradiated ex vivo to prevent transfusion-associated graft-versus-host-disease. Recently, ex vivo irradiation of re-transfused wound blood has been proposed to prevent metastatic spread in patients with malignant tumors, an issue requiring different dose concepts. To determine effects on blood cells we examined the impact of various doses of ionizing radiation. Methods: Full blood was irradiated with doses of 10–150 Gy. Potassium, LDH and hemoglobin levels were determined 2 h–96 h after irradiation. The lymphocyte proliferation after irradiation was measured by means of a lymphocyte-transformation assay. The impact of irradiation on mitogen-induced secretion of cytokines was determined by the ELISA technique, and P-selectin expression as an indicator of platelet activation was analyzed by flow-cytometry. Results: Potassium levels increase with aging and irradiation dose. Mitogenic capacity is reduced by over 90% with moderate doses of 10–20 Gy, but a residual proliferation is still detectable up to 50 Gy. No enhancement of extracellular cytokine levels is detectable, but the cytokine release is reduced by radiation. Neither induction of platelet activation nor abrogation of activation has been detected. Conclusions: Doses of 30–50 Gy abrogate lymphocyte proliferation almost completely. In this range we did not observe severe adverse effects on blood transfusions. Hemolysis might be enhanced when the samples are stored for a longer period after irradiation.

Flufenamic acid: Growth modulating effects on human aortic smooth muscle cells in vitro

PURPOSE The aim of the study was to examine the effects of flufenamic acid on proliferation, clonogenic activity, migratory ability, cell-cycle distribution, and p44/42-mitogen-activated protein kinase (MAPK) expression on serum-stimulated human aortic smooth muscle cells (haSMCs) in vitro. MATERIALS AND METHODS HaSMCs were treated with flufenamic acid in three different doses (40 micromol/L, 200 micromol/L, 400 micromol/L) for 4 days, and then flufenamic-acid-free culture medium was supplemented every 4 days until day 20 after initial treatment. The growth kinetics were assessed. Cell-cycle analysis was performed by flow cytometry. The clonogenic activity was evaluated with use of colony formation assays. The migratory ability was investigated by stimulation with platelet derived growth factor (PDGF-BB) in 24 well plates with 8-microm pore membrane inserts. The p44/42 MAPK was detected by Western blot technique. RESULTS Flufenamic acid inhibited the proliferation (400 micromol/L treatment over 4 d; 179,700 +/- 49,800 vs 747,900 +/- 144,000; P <.001), clonogenic activity (400 micromol/L treatment over 4 d; 1 +/- 0.3 vs 50 +/- 1.4; P <.001) and migratory ability (400 micromol/L treatment over 4 d; 8 cells +/- 2 vs 48 cells +/- 15; P <.001) of haSMCs in a dose-dependent manner. Cell-cycle analysis revealed a G2/M-phase block (400 micromol/L treatment over 4 d; 28.9 +/- 1.5 vs 9.5 +/- 3.2; P <.001). The expression of p44/42 MAPK was reduced for a treatment with 400 micromol/L flufenamic acid (controls, 427 BLU +/- 0.305 vs treatment group, 190 BLU +/- 106; P <.05) CONCLUSION Flufenamic acid inhibits the proliferation and migration of haSMCs. Further experiments with animal models concerning stenosis and restenosis are necessary to evaluate the potential of this promising drug.

Do static or time‐varying magnetic fields in magnetic resonance imaging (3.0 T) alter protein–gene expression?—A study on human embryonic lung fibroblasts

To evaluate the influence of magnetic resonance imaging (MRI) on gene expression in embryonic human lung fibroblasts (Hel 299).

Impact of glafenine hydrochloride on human endothelial cells and human vascular smooth muscle cells: a substance reducing proliferation, migration and extracellular matrix synthesis.

The aim of this study was to examine the effects of glafenine hydrochloride (a nonsteroidal anti‐inflammatory drug) on proliferation, clonogenic activity, cell‐cycle, migration, and the extracellular matrix protein tenascin of human aortic smooth muscle cells (haSMCs) and human endothelial cells (ECs) in vitro.

Meclofenamic Acid for Inhibition of Human Vascular Smooth Muscle Cell Proliferation and Migration: An In Vitro Study

AbstractPurpose: The aim of the study was to examine the effects of meclofenamic acid on proliferation, clonogenic activity, migratory ability, cell cycle distribution and p44/42 MAPK (mitogen activated protein kinase) expression in serum-stimulated human aortic smooth muscle cells (haSMCs). Methods: haSMCs were treated with meclofenamic acid in three different concentrations (10 mM, 100 mM, 200 mM) for 4 days. Then meclofenamic acid-free culture medium was supplemented until day 20. Growth kinetics were assessed. Cell cycle analysis was performed by flow cytometry. Clonogenic activity was evaluated with colony formation assays. Migratory ability was investigated by stimulation with platelet-derived growth factor (PDGF-BB) in 24-well plates with 8 mm pores membrane inserts. p44/42 MAPK was detected by Western blot technique. Results: Meclofenamic acid inihibited the proliferation, clonogenic activity and migratory ability of haSMCs in a dose-dependent manner. Cell cycle analysis revealed a G2/M-phase block. The p44/42 MAPK was significantly reduced. Conclusion: Meclofenamic acid inhibits the proliferation and migration of haSMCs. If a sufficient dose of meclofenamic acid can be applied systemically or by local drug delivery it could be a valuable substance to prevent restenosis after angioplasty.

MRI‐compatible incubation chamber for cell culture experiments

To develop an incubation chamber that is compatible with MRI, while avoiding sources of error due to the experimental setup.

Antiproliferative effects of the antiallergic agent azelastine on human aortic smooth-muscle cells: an in vitro study.

Schöber W, Wiskirchen J, Kehlbach R, et al. Antiproliferative effects of the antiallergic agent azelastine on human aortic smooth-muscle cells: an in vitro study. Invest Radiol 2002;37:248–253. rationale and objectives. The aim of the study was to examine the effects of azelastine on proliferation, clonogenic activity, cell-cycle, and migration of human aortic smooth-muscle cells (haSMCs) in vitro. methods. HaSMCs were treated for 4 days with azelastine (1 &mgr;mol/L, 25 &mgr;mol/L, 50 &mgr;mol/L). Half of the treated groups were incubated again with azelastine, the other half received azelastine-free medium every 4 days until day 20. The growth kinetics and clonogenic activity were assessed. The cell-cycle distribution was investigated by FACS - analysis and the migratory ability was evaluated. results. Azelastine inhibited the proliferation and the clonogenic activity of haSMCs in a dose dependent manner. A G2/M-phase block was induced and the migratory ability was significantly impaired. conclusion. Azelastine has the potential to inhibit the proliferation of haSMCs. If a sufficient dose can be applied either systemically or locally it could be a valuable substance to prevent restenosis.