Johann Kummermehr
Ludwig Maximilian University of Munich
IrradiationRadiologySurgeryPathologyCellIn vitroRadiosensitivityCarcinomaOral mucosaFemurStem cellNuclear medicineEpidermoid carcinomaBasal cellExternal beam radiationCancer researchRadiation therapyRadioresistanceMedicineBiology
Publications 18
#1Mechthild KrauseH-Index: 59
#2Daniel ZipsH-Index: 43
Last. Michael BaumannH-Index: 68
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The combination of molecular-targeted agents with irradiation is a highly promising avenue for cancer research and patient care. Molecular-targeted agents are in themselves not curative in solid tumours, whereas radiotherapy is highly efficient in eradicating tumour stem cells. Recurrences after high-dose radiotherapy are caused by only one or few surviving tumour stem cells. Thus, even if a novel agent has the potential to kill only few tumour stem cells, or if it interferes in mechanisms of ra...
#1Johann KummermehrH-Index: 11
#2Eirik MalinenH-Index: 22
Last. Klaus-Rüdiger Trott (QMUL: Queen Mary University of London)H-Index: 11
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Abstract Purpose: To study the influence of tumor fibroblasts on radiosensitivity and stem cell fraction of tumor cells in squamous cell carcinoma megacolonies by determining colony cure and clonogen survival. Methods and Materials: Murine squamous cell carcinoma cells (AT478c) grown as flat but multilayered megacolonies were co-cultured with pre-irradiated tumor fibroblasts derived from the same carcinoma, and irradiated with 1, 2, 4, or 8 fractions. Recurrent clones and their growth pattern in...
Abstract Purpose: To develop a method to analyze regrowth delay times, including cured tumors. Methods and Materials: Regrowth delay measured in the in vitro squamous cell carcinoma megacolony system following fractionated irradiation was analyzed using two different approaches. A conventional regrowth delay analysis based on means or medians of dose groups was contrasted with a one-step procedure using the inverse of individual regrowth delay times, where cured tumors are represented by an infi...
#1Michael ArnoldH-Index: 1
#2Paul StasH-Index: 1
Last. Klaus-Ruediger Trott (QMUL: Queen Mary University of London)H-Index: 2
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Abstract Background and purpose : Impairment of osseous healing in treatment combining surgery and radiotherapy is a frequent complication. Its dependence on sequence and interval was studied in a defined experimental model. Materials and methods : The effect of pre- and postoperative irradiation by single doses of X-rays on osseous closure of a 1.2 mm drill hole in the rat femur was measured 6 or 7 weeks after surgery in histological sections using morphometrical methods. Results : Irradiation ...
#1Rafal TarnawskiH-Index: 20
#2Johann KummermehrH-Index: 11
Last. K.R. TrottH-Index: 4
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Abstract Purpose : To measure changes in spontaneous growth rate and radiation response in the progeny of irradiated squamous cell carcinoma cells. Materials and methods : Murine SCC cells of the line AT478 were grown as epithelial megacolonies in vitro, using both the original line and two subsequent passages derived from a clone that had recurred after a high radiation dose. Radiosensitivity was evaluated in terms of local control following single dose irradiation of standard size megacolonies...
#1H.-J. Krämling (LMU: Ludwig Maximilian University of Munich)H-Index: 5
#2J. GrabH-Index: 3
Last. K. KrimmelH-Index: 2
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#1S. Schultz-HectorH-Index: 3
#2P. Brechenmacher (LMU: Ludwig Maximilian University of Munich)H-Index: 1
Last. H.-J. Krämling (LMU: Ludwig Maximilian University of Munich)H-Index: 5
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Abstract An experimental model in the rabbit is presented which is suitable for analysis of clinically relevant, early side-effects of combined upper abdominal IORT and ERT. Fractionated ERT alone given through an upper abdominal a.-p. field including the entire stomach caused gastric ulcerations within ≤ 58 days. Latent times decreased with increasing dose and the ED 50 for occurrence of ulcers was 39 ± 3.3 Gy. Single doses of IORT of 20–40 Gy alone administered through a 2-cm diameter field lo...
Summary The tolerance of most normal tissues and the radioresistance of some and maybe most tumors increases as overall treatment time increases. In most cases this increase appears to be proportional to time. The time factor is measured by the additional dose that has to be delivered for a given additional time period to achieve the same effect, and is quantitated as Gy/d. Typical values for the time factor in human tumors, particularly squamous cell carcinomas, are between 0.4 and 1 Gy/d, but ...
#2A. ZajuszH-Index: 6
Last. Klaus-Rüdiger TrottH-Index: 11
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Abstract In 16 patients treated for squamous cell carcinoma of the oral cavity or oropharynx with an accelerated split course regimen, acute mucosal reactions were significantly less in the left buccal mucosa which had been repeatedly painted with 2% silver-nitrate solution for several days before radiotherapy than in the unpainted right buccal mucosa.
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