Showing papers by "Horst Feldmann published in 1991"

Hyperthermia in eccentrically located pelvic tumors: excessive heating of the perineal fat and normal tissue temperatures.

Abstract: Regional hyperthermia in deep-seated tumors can be limited by excessive heating of normal tissues, usually associated with pain or local discomfort. In this report, 57 hyperthermia treatments in 8 patients with locally advanced presacral recurrences of colorectal cancer were analyzed with respect to normal tissue temperatures, especially with respect to the perineal fat temperature. In 27 treatments, 1 to 2 catheters had been inserted from the perineal region through a large part of the perirectal and presacral fat into the tumor, so that temperature profiles of the perineal fat could be obtained. The mean maximum temperature (±SD) of the vagina, rectum, bladder, muscle tissue, and perineal fat was 40.8 ± 1.2°C, 40.9 ± 1.6°C, 40.5 ± 1.6°C, 39.8 ± 0.7°C, and 42.6 ± 1.1 °C, respectively. The mean maximum systemic temperature (±SD) was 37.7 ± 0.7°C. In 42% of the treatments, the temperature in the perineal fat ranged between 43 and 46°C and was treatment-limiting. In conclusion, overheating of the perineal fat is a problem in the treatment of eccentrically located tumors of the presacral region when relatively high temperatures in the tumor will be maintained for longer time periods.

The use of a synthetic tRNA gene as a novel approach to study in vivo transcription and chromatin structure in yeast

Abstract: To monitor in vivo transcription and chromatin structure of yeast tRNA genes, we constructed a synthetic tRNA gene that can be used as a reporter. Constructs in which this synthetic tRNA gene is combined with different flanking regions can be integrated into the genome as single copies. The artificial tRNA gene is tagged by the insertion of an intron-like sequence that cannot be spliced out from the precursor and transcripts can thus be identified and quantitated. By several criteria, the artificial tRNA gene behaves like a resident tRNA gene. By measuring the accessibility towards DNaseI in chromatin, we found that the artificial tRNA gene exhibits the same characteristic pattern as resident tRNA genes. Three DNaseI-sensitive sites across the transcribed part of the gene and the immediate flanking regions reflect the formation of the stable transcription complex; positioned nucleosomes are observed in the upstream flanking region. We are confident that the system we have established will prove useful for studying regulatory aspects of tRNA gene expression as well as aspects of pre-tRNA processing and splicing.

Postoperative radiotherapy of salivary gland tumors. Prognostic factors and treatment results

Abstract: A retrospective analysis of 63 patients with malignant major salivary gland tumours treated between 1972 and 1988 is presented. In 54 patients the tumour was located in the parotid gland, in the remaining nine patients the tumour was located in the submandibular gland, 31 patients were treated for stage I to II disease, 32 patients for stage III to IV disease. All patients were irradiated postoperatively using 60 Co. 137 Cs photons or electrons of adequate energies. As basic techniques ipsilateral portals, a wedge pair of portals or parallel opposed fields were used. The target doses ranged between 45 and 70 Gy with fractions of three to five times 2 to 3 Gy weekly, dependent on postoperative status and stage. In 25% of the patients a local recurrence was evident after radiotherapy with 13% developing distant metastases. The five-year survival was 95% for stage I, 83% for stage II, 30% for stage III and 7% for stage IV. Additionally, the prognosis varied according to lymph node involvement, grading and microscopic or macroscopic residual disease.