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Biomedical subjects

U Ganzer

Publications and source records attributed to U Ganzer.

At least 73 records · Page 4Linked to original sources
PubMed1978

The distribution of Feulgen stained nuclei in the periphery of human head and neck tumours--cytophotometric investigations.

With single cell cytophotometry we investigated the distribution of Feulgen stained cell nuclei of ENT tumours. In the periphery of exophytically growing tumours these cells seem to be distributed homogeneously. Because of the difficulties in determination of the DNA synthesizing cells Feulgen cytophotometry should be completed by other cell kinetic methods e.g. pulse cytophotometry and autoradiography.

Cell Cycle↗
PubMed1978

[The mode of action of bleomycin-cell kinetic investigations (author's transl)].

Chemotherapy of malignant ENT tumours with Bleomycin (BLM) alone is not very successful. In the last time however several authors pointed out much better therapeutic results when BLM therapy has been combined with radiation treatment It is farly unknown why this combination should cause a greater therapeutic effect. Therefore we investigated the following questions: 1. In what manner does BLM influence the kinetics of cell proliferation of malignant tissues? 2. Does BLM synchronize the tumour cells or is the greater therapeutic success of a combination of BLM and X rays only depending an an additional effect? 3. Can we find a connection between the effect of BLM and the histology of the tumour? With cell kinetic methods (authoradiography, cytophotometry, mitotic index) and histological technics we examined these problems in 5 human ENT tumours and got the following results: 1. BLM initially causes a partial synchronization of the tumour cells (blockade in the S-phase). During a continuous therapy with BLM however the tumour cells will be collected in the late S- and mainly in the G2-phase. But this peak of cells in G2 is not the expression of synchronization because a lot of these cells are blocked irreversible and will leave the cell cycle (hyperceratotic cells). Ffrom those cells which thereupon have entered the mitotic phase a further part of them will by endomitosis or endoreduplication. Only a small group of the cells originally collected in the G2-phase will devide and enter the G1-phase again. Furthermore we observed a distinct recruitment of G0-cells back into the cell cycle (for details see fig. 9). 2. The greater effect of radiation therapy following the application of BLM is not the result of synchronization but of an additional destruction of premitotic G2-cells which properly would have undergone mitosis. BLM and X rays therefore act additionally. 3. The greater therapeutic success of the combination of BLM and radiation treatment comes true only in keratinizing squamous cell carcinoma. The reason is that BLM destroys the tumour cells by hyperkeratosis and polyploidy. Thus BLM must be ineffective in carcinoma without the ability of keratinizing.

Bleomycin↗
PubMed1977

[Critical reflections to the problem of timing in the synchronization therapy of human malignant tumors. Mitotic-index determination, cytophotometric and radioautographic studies (author's transl)].

Formerly (1969) we have been able to demonstrate that during a lengthy inhibition of the DNA synthesis with 5-fluoro-uracil (FU), cells assemble just before, at the outset of, and within the S-phase. By taking off the inhibition, these cells start off together for the rest of the life cycle and pass the S, G2 and M phase like a wave. By the experimental condition given, the time required for passing the S phase was rather constant for all tissues. It generally took about 8 h. The sensitivity of cells to radiation depends on the current phase of their life cycle. Normally they are highly radiosensitive during the transition from G1 to S phase and within the G2 phase. Therefore we tried to improve the effectiveness of radiotherapy by radiating the synchronized cell population in the G2 phase. In clinical treatment we give an infusion with 1 g FU in 1000 ml 5.4% Glucose for 12 h. 8--9 h after the end of the infusion radiation will be applied (Betatron, individual doses: 500 rad). This treatment will be repeated until a total dose of 5000--6000 rad. Until now nearly 300 cases of patients treated in this way have been published. The 5 year-results show only in about 60% of the patients a fast reduction of the tumor. The long term results are unsatisfactory. Beside many other points the most important reason for these clinical results might be the individual length of the S phase of the tumors which prevents that radiation can be given exactly in G2 phase in each case. With mitotic-index determination, with cytophotometric investigations and the double labelling technique (3H- and 14C-Thymidine) we therefore tried to find an answer to the following questions: 1. How long is the DNA synthesis time in the individual case of human ENT tumors? 2. Does the application of FU influence the length of the S phase? 3. Will the synchronization-degree become higher by using other methods of cell cycle inhibition? With the above mentioned experimental methods we found that the length of the S phase in human tumor spreads from about 8--16 h in the individual case. The application of FU has no influence on DNA synthesis time. By using FU the degree of synchronization is about 2.5 in according to former experimental work and that of other authors. These results will be discussed in detail as well as the conclusion we draw from our experiments: to give radiation not in G2 but in G1/S of the cell cycle. Long-term observation of the patients and further animal experiments shall demonstrate whether this technique of synchronization therapy will improve the clinical results.

Autoradiography↗
PubMed1977

[Pathogenesis and clinical observations of papillomatous diseases of the skin and of the mucous membranes (author's transl)].

In the certain skin-warts, condylomata acuminata, oral-, laryngeal- and bronchial papillomas a morphologically identic virus is often seen. This virus belongs to the papova-virus-group and causes papillomas: Independant of their localization their clinical behaviour is very similar. Using cytophotometric methods we tried to find out if there are any signs which allow to reveal malignancy in continous reappearing papillomas.

Adult↗
PubMed1977

[Chronic mucous effusions of the middle ear and the influence on inner ear function (author's transl)].

Audiometric recordings of children suffering from chronic mucous effusion of the middle ear have revealed a statistically significant and permanent sensorineural hearing loss of high frequences. Attemps for mechanical or physical factors as explanation are not convincing. We believe that inner ear disturbances in chronic mucous effusion rise by direct intoxication of the basal turns of the cochlea caused by pathologic alterations of mucous membrane tissue. Certain substances like lysozymes or histamine are supposed to diffuse via round window membrane to the inner ear. On the other hand mucous effusion which fills the middle cavity prevents oxygen to diffuse from the middle ear to the inner ear. Maass et al. (1976) and Morgenstern (1977) clearly have shown that under physiological conditions oxygen tension in the perilymph of the basal cochlear turn partly depends on diffusion from the middle ear. The results of our clinical observations indicate that early diagnosis and prompt treatment is necessary to prevent permanent sensorineural hearing loss of high frequencies, especially in infants and children.

Audiometry↗
PubMed1976

[Results of bleomycin therapy in recurrent head and neck tumors (author's transl)].

40 patients with previously treated recurrent head and neck carcinomas have been treated with Bleomycin. The total dose of drug administered ranged from 360-600 mg. In three patients, treatment had to be interrupted because of severe side effects of the drug. Temporary complete disappearance of tumor occurred in three patients, whereas incomplete tumor regression briefly occurred in one third of those patients treated. Survival time for all patients averaged three months. A possible immunosuppressive effect of Bleomycin is also discussed, as based on clinical observations noted in one of the patients treated.

Bleomycin↗
PubMed1975

[The treatment of inoperable juvenile angiofibromas (author's transl)].

Demonstrating a case of juvenile angiofibroma penetrating the base of the scull and growing mainly endocranially we refer to Honvan (Fostestrolum) treatment of this kind of tumor. The effect of this treatment can be shown histologically as a distinct sclerosis of the tumor tissue. Even in long term application of this drug only very few side effects are found.

Adolescent↗