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Biomedical subjects

D Hecker

Publications and source records attributed to D Hecker.

At least 37 records · Page 2Linked to original sources
PubMed1979

[Electron microscopical and enzyme histochemical investigation of kidney and liver of the albino rat after cytostatic treatment (author's transl)].

Within 5 days following treatment with cytostatics (vincristine, vinblastine, trenimon, 5-fluorouracil) enzyme-histochemical and ultrastructural changes occurred in the kidney and liver of Wistar rats. The enzyme activities were influenzed by cytostatics in different ways. It was found that the activity of some enzymes increased whereas that of others decreased. Kidney and liver showed a different response in their enzymatic behaviour. The cytostatics used did not have the same effect. The histochemical changes following injection of cytostatics in juvenile rats do not agree with those in adult ones. The electronmicroscopic findings reveal marked morphological changes of the kidney and liver cells within the first 5 days following injection of cytostatics. From the 8th day on after administration of cytostatics neither histochemical nor ultrastructural changes as compared with the controlls were found.

Animals↗
PubMed1978

[The correlation of in vivo and in vitro effect of cytostatics in transplantated tumours of the mouse (author's transl)].

In 2 inoculated mouse tumours the conformity of the actions of 4 different cytostatics at 2 dose levels was tested in vitro and in vivo. The histochemical reaction of lactate dehydrogenase and NADH diaphorase was taken as a criterion of the cytostatic action. The investigations showed the tumours used responded to the cytostatics employed. A good conformity of the in vitro and in vivo findings was established. The histochemical assessment of organ cultures following the administration of cytostatics allows to determine the sensitivity of tumours and helps the physician in deciding on an effective therapeutic.

Animals↗
PubMed1977

[Nuclear alterations on organ cultures of human malignant melanomas (author's transl)].

Report on ultrastructurally striking nuclear anomalies in organ cultures obtained from amelanotic and pigmented human melanomas. These nuclear anomalies are more impressive than the nuclear invaginations present in tumours cells of several other malignant growths. Numerous nuclear fragments varying in size and held together by nuclear membrane bands may occur. The karyoplasm of these nuclei reveals nothing unusual no degenerative changes can be found.

Cell Nucleus↗
PubMed1977

[Histochemical and ultrastructural investigations on the activity of methylglyoxal (bis)-guanylhydrozan (methyl-GAG) on organ cultures of malignant tumors (author's transl)].

Methyl-GAG was tested in organotypic cultures of malignant tumors of human and mice. In 3 cases, a reduction of the activity of two oxydoreductases (lactate dehydrogenase and NADH-diaphorase) after treatment with methyl-GAG was observed whereas in 19 other cultivated tumors no change of enzyme activity was induced by methyl-GAG. Electronmicroscopy revealed only minor structural alterations of tumor cells after application of methyl-GAG as compared with control cultures.

Animals↗
PubMed1977

[Investigations on acceleration of processes of differentiation and aging in rats after influence of x-ray (author's transl)].

On the basis of the hypothesis of a relation between the processes of differentiation and aging in connection with the assumption, that ionizing radiation accelerates the aging of organism, the authors investigated the changes in the cellular reaction in organ cultures of the spleen and the kidney, in the pattern of enzymes in the kidney and the liver and moreover the behaviour of the serum protein level. In dependence of the x-ray dosis and the length of time after radiation an acceleration of the processes of maturation and differentiation could be observed with the three above mentioned methods. Changes could be found which were similar to those, observed in adult or senile rats. The latent phase or organ cultures was prolonged as well as the morphology of cells migrating out of the explants did not differ from that of senile donor animals. The chemical differentiation of the kidney is accelerated after radiation. The detected changes were similar to those in adult or senile rats. The increase in the albumin, haptoglobin and transferrin concentrations of juvenile rats following radiation mean an acceleration of development, for these concentrations are attained during normal development. The authors discuss their results with reference to the existing theories of aging.

Aging↗
PubMed1977

[Enzyme histochemical and electron microscopic studies on the problem of infiltrating (invasive) tumor growth. 2. Electron microscopic studies].

Tumour cells of 12 mammary carcinomas, 14 ovarian carcinomas, 10 malignant melanomas of the man and 24 transplantation tumours of rats were studied by the electron microscope in their relation to the surrounding tissue. On the contact surface between tumour cells (mammary carcinomas) and surrounding tissue a focal or extensive loss of the cell membranes in seen. This causes a release of cytoplasmic parts, especially of ribosome-like material. The adjacent connective tissue shows a splitting of the collagenous bundles and a fibrilloysis. In the infiltrated skeletal muscle (ransplantation tumours of rats) the tumour cells connect directly to the muscle cells. These are eroded showing ruptured fibres and loosened filaments and mitochondria, giving a moth eaten appearance. As a result of these findings we presume that the destruction of the tissue surrounding the tumour is mainly initiated by the tumour cells. For ovarian carcinomas and malignant melanomas (with few exceptions) there is no morphological sign for a specific enzymatic-lytic effect of the living tumour cells to the surrounding tissue. The findings are discussed in the aspect of the invasive tumour growth.

Cell Nucleus↗
PubMed1976

[Histochemical and ultrastructural investigations on organ culture of malignant tumors (author's transl)].

Organ cultures of malignant tumours were histochemically and electronmicroscopically investigated. There was established that follows enzymes show a little activity in cultured tumour cells after 24 and 48 h: succinate dehydrogenase, alkaline phosphatase, adenosine triphosphatase, and nonspecific esterase, whereas NADH-diophorase, lactate dehydrogenase, and acid phosphatase show an essentially higher activity after termination of the cultivation. However, in comparison with the primare tissue, the activities of the last mentioned enzymes are clearly decreased in cultured tumour cells after termination of the cultivation. No changes of cell structures have electronmicroscopically been observed on these cultures of malignant tumours.

Animals↗
PubMed1976

[Investigations for using cell- and organ culture in sensibility tests for cytostatics in human ovarial-carcinomas (author's transl)].

Comparison was proved from meaning of cell culture and organ culture in therapeutic sensibility tests for cytostatics in ten human ovarial-carcinomas. The sensibility for cytostatics was determined with morphological criteria in cell culture and with the activity-patterns of some enzymes (lactate-dehydrogenase, NADH-diahorase) in organ culture. In these investigations the tumors have shown approximate conformity in the state to cytostatic-sensibility as seen with the two different methods. It seems to be possible, according to these investigations, to use enzyme-histochemical parameters from organ culture for inquiry of cytostatic-sensibility of tumors.

Antineoplastic Agents↗
PubMed1974

[Application of morphological and histochemical methods for evaluation of cytostatic effects on organ cultures of malignant tumors].

Histochemical and morphological methods are reported to test the sensitivity of organ culture of human and animal tumors to cytostatics. Topochemical investigations of lactate-dehydrogenase and NADH-diaphorase in organ culture of UV-induced mice tumors have shown that there is a considerably decreased enzyme activity, as compared with the controls, after application of a clinical as well as a tenfold clinical dose, especially after treatment with trenimon and 5-fluorurazil. On the other hand a decreased activity of these enzymes was found in organ cultures of tumors induced by methylcholanthren, following application of vinblastin and 5-fluorurazil. Three out of five of the investigated mammary carcinomas exhibited a markedly decreased enzyme activity when tested with cytostatics. Furthermore, a significant decrease of the enzyme activity was observed in two ovarian carcinomas and in two malignant melanomas of three tumors examined in each case. Following the administration of cytostatics, electronmicroscopical studies showed marked changes in the mitochondria in mammary carcinomas as well as in ovarian carcinomas, whereas no alterations were found in melanomas. The findings are discussed in the light of individual chemotherapy of cancer.

Animals↗