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Biomedical subjects

K H Kärcher

Publications and source records attributed to K H Kärcher.

At least 19 recordsLinked to original sources
PubMed1993

X-ray induced DNA double-strand breakage and rejoining in a radiosensitive human renal carcinoma cell line estimated by CHEF electrophoresis.

Cell intrinsic radiosensitivity is of great importance in radiation therapy, but its molecular basis is still uncertain. Since DNA double strand breakage is considered to be the most important lesion related to cell death induced by ionizing radiation, the relationship between DNA double-strand breakage, repair and cell survival was investigated in three cell lines: Chinese hamster cell (CHO-K1), human fibroblast and human renal carcinoma (Tu 25). The D0 values after X-irradiation were 1.73, 1.23, and 0.89 Gy, respectively, showing that Tu 25 was the most sensitive among them. DNA double-strand breaks were measured by CHEF electrophoresis, the initial yield of double-strand break per dose in the three cell lines was almost the same, and no correlation to cell survival was found. However, the rejoining capacity for DNA double-strand break differed. After a dose of 20 Gy, the repair rate was markedly lower in Tu 25, with a half repair time of 40 min, as compared with the other two cell lines with half repair times of 15 min. The results strongly supported the correlation between the repair capacity for DNA double-strand break and cell survival. It was concluded that DNA repair capacity is one of the determinants of cell radiosensitivity. Estimation of DNA double-strand break rejoining by CHEF was suggested as a predictive assay for radiosensitivity of human tumor cells.

Animals↗
PubMed1993

[Potentialities and limitations of combined radiotherapy-surgical treatment of large orofacial T3/T4 tumors].

The possibilities, limits and good cosmetic and functional results of combined radiotherapy-surgical treatment of large orofacial tumors (T3) are prescribed. The pre- and postoperative split radiotherapy with operation in between is favoured. The radical en-bloc-resection with radical neck dissection is the surgical therapy of choice. The defects have been reconstructed with osteomusculocutaneous flaps.

Combined Modality Therapy↗
PubMed1992

[The prevention of mucosal lesions during oropharyngeal irradiation with a dental-filling shield].

In patients with metallic dental fillings radiation therapy to the oral cavity can cause mucous membrane lesions, which are more severe than expected. They appear as circumscribed erosions, opposite to metallic fillings and are caused by an increase in radiation dose through secondary radiation due to the higher density and atomic number of the filling material. This dose increase can be directly measured with 0.1 mm thin sheets of graphite-loaded TLD's (LiF, Vinten). For Co-60 gamma rays a commercial amalgam filling caused a dose increase by a factor of 1.7. The half value layer for this additional radiation was measured to be approximately 0.4 mm tissue. In order to avoid painful mucous membrane ulcerations which are even more a problem if hyperfractionated treatment schedules are used, we constructed individual dental shields for each patient. As shielding material we used a dental impression material (Optosil P+1 Bayer). This method was tested in 35 patients, in all of them circumscribed mucous membrane ulcerations could be avoided. The method proved to be fast and simple and was very well tolerated by all patients.

Dental Amalgam↗
PubMed1991

[The value of transrectal sonography in assessing radiogenic rectal changes].

The clinical value of TRS in diagnosis and staging of radiogenic rectal disorders is discussed. TRS was performed on 120 patients with tumours of lower pelvis who were treated by radiotherapy. They were divided in this trial into 2 groups. Group I (n = 113, with a mean interval to radiotherapy of 2 years) including patients who were under a routine control. Group II (n = 7, with a mean interval to radiotherapy of 13 years) including patients with strong local pain of the radiotherapy zone. The sonographic changes were divided into 4 grades (0-III) and verified histologically in group II patients by means of biopsy. A control group (n = 35) was also examined by TRS. The patients of this group were not treated radiotherapeutically. We concluded in our study that TRS in radiogenic rectal disorders, give us a very precise grading of the tumours which in turn, is of great importance in the further therapeutic procedure and in the evaluation of tumour recidives and second malignomas of the rectal wall.

Aged↗
PubMed1990

[Therapy monitoring and after care of irradiated anorectal cancer using transrectal sonography].

Pretherapeutic staging before radiotherapy and peri- and posttherapeutic endosonographic screening was carried out on 33 patients with anorectal carcinoma. The results showed the transrectal endosonography to be essential for staging and for the differential diagnosis of tumor recurrence/post irradiation changes during follow up. The sonomorphological criteria of tumor recurrences and post irradiation bowel wall changes are discussed.

Aged↗
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↗
PubMed1989

A new spacing material for interstitial implantation of radioactive seeds.

Poly-p-dioxanon sutures (PDS) have been common in surgery as an absorbable material for years. After hardening by a particular procedure we use PDS pins as spacer material in interstitial I-125 implantations. The advantages of PDS are the mechanical qualities in contrast to catgut which causes hazards because of its soft consistency. PDS supports the efforts in optimization of seed distribution and dose application in interstitial radiotherapy.

Brachytherapy↗
PubMed1988

Radiotherapy of metastatic renal cell carcinoma.

Modern oncological treatment of metastatic renal cell carcinoma may have different goals: first of all, improvement of survival rates; secondly, elimination of symptoms like pain from osseous lesions or disorders of central nervous system functions. Chemotherapy or radiotherapy or the combination of both should improve life quality and be tolerable to the patient. Close interdisciplinary contacts of medical and radiological oncologists are therefore necessary. Radiotherapy should be carried out under conditions of high-voltage energy and modern treatment planning to concentrate and limit the irradiation volume as much as possible. Split-course technique and radiation as interval treatment between chemotherapy courses seem to be optimal. Our clinical results indicate that the reported radioresistance of renal cell carcinoma might result from radiobiological and methodological misinterpretations.

Bone Neoplasms↗
PubMed1987

[Therapy and follow-up using TPA in radio-oncologic after-care in bladder cancer].

Differentiating between a progressive carcinosis and a clinically tumour-free patient, using the data provided by a tumour-marker, is above all else important for the observation of cancer patients whose primary tumour has been surgically removed. The tumour marker TPA was observed postoperatively in 55 patients with carcinoma of the bladder throughout a period of 12 to 36 months before, during and after radiotherapy and compared to the respective clinical condition. Among these patients all stages T1 to T4 of the TNM-system were represented (19) (Tab. 1). Clinical progress remained stationary in 44 cases, whereby TPA was in 19% (n = 8) of the cases in discordance with clinical progress. In 11 cases (7 local recurrences and 4 distant metastasis) clinical progress was observed to be positive, whereby TPA was concordant in 75% (n = 5) of the local recurrences and in 90% (n = 3) of the distant metastases.

Follow-Up Studies↗
PubMed1987

Survival and quality of life in 23 patients with severe aplastic anemia treated with bone marrow transplantation (BMT).

Survival and quality of life are reported in 23 pretransfused patients with severe aplastic anemia (SAA) who underwent bone marrow transplantation (BMT). The projected survival is 76% with 18 of 23 patients being alive 332 to 1677 days post graft (median: 842). 5 patients died between day 4 and 416. 12 of 17 patients at risk developed chronic graft versus host disease (GVH-D). 4 of these patients have a diminished quality of life due GVH-D related disabling manifestations. Autologous haemopoietic recovery was excluded in all patients by the demonstration of haemopoietic chimerism. We recommand age-adapted rejection prophylaxis; such strategy may help to diminish disabling graft versus host disease in otherwise haematologically reconstituted survivors.

Adolescent↗
PubMed1987

[Perioperative radiotherapy of esophageal cancer].

The paper reports on the status of radiotherapy of carcinomas of the oesophagus both preoperatively and postoperatively. It is evident that sufficient radiotherapy in combination with chemotherapy produces an improvement in the lethality rate, but has no effect on the five year-survival rate. The optimal solution is preoperative radiotherapy as practised Nakayama's group, with subsequent postoperative irradiation. The palliative results of megavolt radiotherapy alone are excellent with regard to quality of life, but the overall course of the disease is not affected.

Carcinoma, Squamous Cell↗
PubMed1987

[Optimization of interstitial hyperthermia systems].

After having studied the fundamental possibilities of proceedings allowing an intracorporeal transfer of energy, two systems were investigated in detail in order to achieve a wide range of application: 1. Resistance heating of tissue by modified standard needles and individual regulation of each needle (system KHS-9). 2. Water heating of standard needles as used in interstitial radiotherapy and overall regulation of the total system. These new systems are supposed to be applied in clinical practice and have been developed by GSP-Wien at the suggestion of the University Hospital for Radiotherapy and Radiobiology. Patent is applied for both of them.

Humans↗
PubMed1986

Electron beam therapy in treatment of parotid neoplasm.

In a retrospective analysis, 42 patients with malignant primary tumor of the parotid gland were evaluated considering survival, local recurrence and tolerance of treatment. All patients referred to radiotherapy were treated by electron beam (10-15 MeV) and followed for more than 5 years. Postoperative radiotherapy after radical operation, with no macroscopic disease, was performed in 18 patients, 7 of whom were treated by radical re-operation and radiation of a recurrent parotid neoplasm. In these groups, the local recurrence rate was 4/18 (22%) and 2/7 (29%), the 5-year survival rate was 9/18 (50%) and 5/7 (71%). In 17 patients, radiotherapy started with gross tumor left behind. This group showed a local recurrence rate of 10/17 (59%) and a 5-year survival of 7/17 (41%). Treatment was well tolerated with no major sequelae. Local tumor control and its impact on survival is discussed.

Adult↗
PubMed1986

[Principles of fractionated total body irradiation before bone marrow transplantation].

The hyperfractioned total body irradiation has advantages in tumor control rate, patient tolerance and survival. The technical application is simple and easy to integrate in the daily routine of a radiotherapy department. The reduced time in the life island and the low incidence of acute reactions increases the patients quality of life. It turned out, that single dose TBI is not very suitable. This was already stated by Lester Peters in 1980.

Bone Marrow Transplantation↗
PubMed1985

[Male breast cancer].

Between 1974 and 1982 inclusive 18 male patients were treated for breast carcinoma. 12 patients had postoperative radiotherapy whereas 4 were referred for treatment of recurrent or metastatic disease. One patient showed signs of inflammatory breast cancer and was treated with chemo-radiotherapy and one was being followed up in our department after radiotherapy for prostatic cancer in 1970. Median overall survival was 52 months and the median disease-free interval was 21 months.

Aged↗