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Biomedical subjects

V Budach

Publications and source records attributed to V Budach.

At least 109 records · Page 6Linked to original sources
PubMed1989

Neutron therapy of low grade "pencil" gliomas of the spinal cord: a review of ten cases.

Between 1980 and 1986 ten patients (two males, eight females, median age: 35 years) with spongioblastomas and ependymomas grade I of the spinal cord were treated with fast neutrons from the d(14) + Be reaction after incomplete tumour surgery. Eight patients received three weekly fractions of 0.7 to 1.33 Gy and two patients four weekly fractions of 0.8 Gy to total doses of 7.4 to 10.4 Gy. Two complete and six partial remissions of ataxia and motor disturbances were observed. Bladder dysfunctions in five patients cleared up partially in three cases. In two patients the symptomatology remained unchanged. After a follow-up of eight to 88 months two initially complete and two out of six partial remission were maintained. No severe late effects of the skin have been determined. In summary it is concluded that for incompletely resected "pencil"-gliomas fast neutron therapy seems to be a feasible treatment modality.

Adult↗
PubMed1989

The vascular system of xenotransplanted tumors--scanning electron and light microscopic studies.

A widely used model for investigating basic tumor characteristics and different treatment modalities preclinically is the immune-deficient, athymic nude mouse. This model offers many morphological parallelisms to the clinical situation. The aim of this study is to demonstrate the vascularization pattern of xenotransplanted human melanomas and sarcomas using different methods. Xenotransplanted tumors of 62 congenital thymus-aplastic nude mice were examined ultrastructurally and topographically after corrosion cast and tissue preparation. Quantitative measurements of tumors injected with India ink were carried out to obtain comparable information on the vascular densities in the tumors. Quantitative measurements showed that there is no zonal, topographic arrangement of the vascular densities. Comparisons of the vascular densities in the centers of tumors with the densities in the periphery showed an extreme heterogeneity in tumor vessel distribution, which does not generally support the idea of a better vascularisation in the tumor periphery. Neither in the periphery nor in the center of the tumor regular vessels are to be seen consisting of intimal, medial and adventitial layers. Even the largest peripheral vessels, which often take a tortuous course, consist mainly of an endothelial layer and some perivascular connective tissue only. Areas with high vascular densities could be seen just beneath areas almost free of vessels. Besides endothelial-lined vessels numerous irregular, tumor cell-lined sinusoids are visible both in sarcomas and melanomas. The morphology of the vessels found scanning electron microscopically is generally in agreement with many features described transmission electron microscopically.

Animals↗
PubMed1988

Instability of xenotransplanted soft tissue sarcomas. Morphologic and flow cytometric results.

Human tumors transplanted into nude mice are widely considered to be identical to the tumor of origin. In addition, high histologic constancy of xenografts over many passages is generally accepted. We have checked these prerequisites for a therapy-orientated application of the nude mouse model using soft tissue sarcomas. Twenty-two primary soft tissue sarcomas and their xenografts were compared histologically and flow cytometrically over numerous passages. More than 30% of transplants showed a variation in cell differentiation, cell content, frequency of mitosis, tendency to necrotize, and connective tissue content compared to the original tumor. Furthermore, transplants from various regions in one tumor showed divergent results. Analyses of serial transplants showed histologic and flow cytometrical discrepancies in about 50% of cases, and new cell lines occurred in 26%. Our results show that the genetic instability found in human neoplasias also applies to xenotransplants and that the therapy-related usefulness of the nude mouse model is limited.

Animals↗
PubMed1988

Preliminary experimental results with the nitrosourea derivative ACNU in the treatment of malignant gliomas.

Comparative studies were carried out to evaluate the cytotoxic effectiveness of the nitrosureas ACNU (Nimustine) and BCNU (Carmustine) at equitoxic dose levels in xenografts from two astrocytomas grades III/IV (Li, Re) and one oligodendroglioma grade III (Oe) on nude mice. Growth delay was measured as the endpoint. All tumours were characterized initially and at regular intervals in later passages as to their histomorphologic pattern, expression of glial fibrillary acid protein and DNA-content by means of flow cytometry. These characteristics were shown to be unchanged in our xenografts over more than 27 passages. Growth delays of 18.7 days (ACNU) and 2.4 days (BCNU) for the Li-xenograft (p less than 0.01) were observed at an LD10 for both drugs. For the Re- and Oe-xenografts, growth delays of 18.0 vs. 14.0 days (p less than 0.001) and greater than 27.0 vs. 14.2 days (p less than 0.02) were observed at an equitoxic dose of 33 mg/kg ACNU or BCNU i.p., respectively. These preclinical data suggest a therapeutic advantage with ACNU for these high grade gliomas and should encourage further experimental and clinical investigations.

Animals↗
PubMed1988

Dosimetry of a new holding device for fast d (14) + Be-neutron irradiation of human xenografts in nude mice.

Fast neutron irradiation of human xenografts in the flanks of nude mice is mainly a technical problem. The feasibility is dependent on the distribution of the tumor absorbed dose DT and on an effective shielding of the bodies of the animals. Therefore a special holding device for simultaneous irradiation of two tumour-bearing animals was developed. Meticulous dosimetric investigations using TLD-300 detectors in a mouse phantom showed that a relatively homogeneous dose distribution could be achieved in the xenografts and that effective shielding of the mice from direct irradiation would be achieved; the dose for the bodies of the animals being less than 10% of the dose to the tumour. Thus survival and a sufficient follow-up period of the irradiated animals could be guaranteed for all preclinical dose ranges used.

Animals↗
PubMed1988

[Heterotransplantation of a human glioma and brain metastases in the athymic nude mouse--a preclinical model for radiation oncology. 1. Basic principles and methodology].

In spite of the great efforts undertaken in the different disciplines, the prognosis of patients with highly malignant gliomas, i.e. astrocytomas of degrees III and IV remains unfavorable. Up to now, new findings about an improvement of radiooncologic therapy methods are obtained retrospectively from the results of complex and time-consuming clinical studies. The heterotransplantation of human tumor tissue in immune-deficient nu/nu mice gives the opportunity to check preclinically the efficiency of different fractionation schemes and cytostatic drugs already. The author's experiences and therapy results are presented in order to demonstrate the possibilities as well as the limits of this in-vivo model performed with a view to clinical conditions.

Animals↗