Biomedical subjects

K Wayss

Publications and source records attributed to K Wayss.

At least 55 records · Page 3Linked to original sources

PubMed1975

[Incorporation of a 131-iodine-deoxycytidine monophosphate protamine complex into the DNA of tumor-bearing rats following partial synchronization with hydroxyurea].

The incorporation of 131-Iodo-deoxyuridine in rat tumours can be increased by partial synchronisation with hydroxyurea. The reported investigation was carried out to determine whether the incorporation could be further increased by using a basic 131-Iodo-deoxycytidine-monophosphate-protamine complex as a depot of Iodo-deoxyuridine. It was shown that the incorporation observed after synchronisation could be increased by using this complex (non-synchronized tumours 1,46% retention, synchronized tumours 2,28% retention; measured 4 hour after the final injection of hydroxyurea) whereas in a control group injected with 131-Iodo-deoxycytidine-monophosphate alone, only a small increase was observed. The large increase in activity in the liver and in the spleen (liver: non-synchronized 2,76%, synchronized 2,79% retention; spleen: non-synchronized 3,00, synchronized 3,80% retention; measured 4 hours after final injection of hydroxyurea) which is observed after injection of the 131-Iodo-deoxycytidine-monophosphate-protamine complex renders it unsuitable for use in the scintigraphic detection of tumours. 131-Iodo-deoxyuridine is shown to be more suitable for this purpose.

Animals↗

PubMed1975

[Possibilities and limits of pre-therapeutic neoplasm sensitivity cytostatics tests under short-term conditions].

The following cytostatic agents were tested for activity in vivo and in vitro inWalker carcinosarcoma 256 of the rat: cyclophosphamide, triaziquon, 5-fluorouracil, methotrexate, adriamycin, dactinomycin, daunorubicin, hydroxyurea, procarbazin and vincritine. With the exception of vincristine, the results of therapy in vivo could be predicted by using a rapid in vitro test system. This involved, for cyclosphosphamide, triaziquon, adriamycin, and daunorubicin, the measurement of 3H-uridine or 3H-thymidine incorporation. The activities of methotrexate and 5-fluorouracil could be determined from 3H-deoxyuridine incorporation and that of dactinomycin from 3H-uridine incorporation. The results of short-term tests (uring adriamycin, daunorubicin, and dactinomycin) in roughly 100 human tumors were compared with data in the literature on therapy with the same cytostatic agents. Good agreement was found between the results of in vitro tests and the literature data on clinical therapy.

Animals↗

PubMed1975

Sensitivity tests of tumors to cytostatic agents. I. Comparative investigations on transplanted tumors in vivo and in vitro.

With series of transplanted tumors, the activities of different cytostatic agents which directly influence the metabolism of nucleic acids (Actinomycin D, adriamycin, daunomycin, 5-fluorouracil, procarbazine, trenimon) was measured by determining 3-H-uridine incorporation in short-term (3hrs) incubations of tumor cell suspensions. Data obtained could be used to predict the response of each tumor to particular cytostatic agents in vivo. The activities of the cytostatic agents as determined using long-term tissue cultures (time of exposure of tumor cells to cytostatic agent 48 hrs were comparable to those obtained with the short-term test. In long-term cultures, determination of cell numbers gave results similar to those obtained by morphological evaluation. In SHORt-term test, differing sensitivities of tumors to cytostatics could be detected.

Adenocarcinoma↗

PubMed1975

Sensitivity tests of tumors to cytostatic agents. II. Investigation on human tumors.

Certain substances which influenced nucleic acid metabolism were found to have about the same cytostatic activity on human cells when measured in tissue culture experiments (cell numbers) or in short-term cultures (3-H-uridine incorporation in cell suspensions). By treatment with a dose of cytostatics corresponding to 10 times therapeutic dose, chemosensitive tumors can be distinguished from non-responsive tumors. By using this in vitro test system to investigate the sensitivities of 100 human tumors, it is shown that 28 of these tumors were responsive to adriamycin, daunomycin and Actinomycin D. Good agreement was observed between these in vitro results and the literature data on clinical therapy using these particular substances.

Antineoplastic Agents↗

PubMed1975

[The effect of cyclophosphamide on tumors in the sensitivity-test (author's transl)].

The sensitivity of tumors to cyclophosphamide was tested in vitro. For this purpose, the urine of cyclophosphamide-treated rats (90 min., 500 mg/kg) was used. This method of activating cyclophosphamid proved more advantageous than other methods; all cytostatically effective metabolites can be used in the test and the production of metabolites can easily be standardized. Consequently results with good reproducibility can be obtained. In various long-term and short-term test models with animal transplantation-tumors in vitro, the effects of the cyclophosphamide metabolites depended on the dose used. This test results in the various test models are comparable. In the tissue-culture of tumors (long-term test) sensitivity was evaluated by using morphological criteria as well as by counting cell numbers. In the short-term test the sensitivity of tumors was found out by influencing the nucleic acid syntheses (3-H-thymidine-, 3-H-uridine-incorporation). As the tissue-culture meets with difficulties as a routine clinical examination, the use of the short-term test is recommended. Using as model the fast proliferating WALKER-256-carcinosarcoma and a slowly proliferating rat adenocarcinoma, the results of the sensitivity-test in vitro were compared with the effects of therapy in animal tests. Tumor remissions corresponding with the results reached in vitro, which depended on dosis, could also be achieved in both transplantation-tumors. Human tumors, tested in in vitro studies (short-term-test), show a different sensitivity to cyclophosphamide.

Adenocarcinoma↗

PubMed1975

[Correlation of in vitro testing and therapeutical results in animal transplanted tumors after cytostatic treatment].

The antineoplastic activity of 5 substances was tested in vivo and in vitro on four different tumours (plasmocytoma and melanoma Fortner III of the Syrian golden hamster, the Walker carcinosarkoma 256 and an adenocarcinoma of the rat). The substances involved were 2,3,5-triethyleniminobenzoquinone-(1,4) (triaziquone), actinomycin D, podophyllinic ethylhydrazide (mitopodozide), bleomycin and adriamycin hydrochloride. The effect of the substances in vivo was measured on the size of the tumour, and in vitro on the incorporation of 3-H-thymidine and 3-H-uridine in short-term incubations of tumour-cell suspensions. No correlation was observed between the 3-H-thymidine incorporation in vitro and the response of the tumours in vivo. On the other hand, the 3-H-uridine incorporation in the tumour-cell suspensions in vitro was in good agreement with the results of therapy in the animal experiments. This is compatible with the results of earlier experiments using other substances to investigate the possible correlation between tumour therapy and in vitro tests.

Adenocarcinoma↗

PubMed1975

[Sensitivity tests of malignant tumours against cytostatic agents in vitro and in vivo/studies on the mouse sarcoma 180 (author's transl)].

The effects of ten different substances on the mouse sarcoma 180 have been compared using in vivo and in vitro test systems. The size of the tumours was taken as a measure of the success of the therapy in animal experiments. The in vitro effects were estimated by measuring the incorporation of radioactively labelled uridine in tumour cell suspensions from solid tumours, in ascites tumours and in tissue culture. Similar results were obtained using all three in vitro test systems. Four substances (daunomycin, fluoruracil, actinomycin D, adriamycin) exhibited activity both in vivo and in vitro, whereas five substances (cytosinarabinoside, methotrexate, ibenzmethyzin, triaziquone, bleomycin) showed no activity in any of the test systems used. With podophyllic acid ethyl hydrazide, however, no correlation between in vivo and in vitro effects was observed. Studies on the influence of the cytostatic agents on the rate of transport of uridine into the cells showed that podophyllic acid ethyl hydrazide strongly reduced the permeability of the cells to radioactive uridine.

Animals↗

PubMed1974