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Biomedical subjects

L Kopper

Publications and source records attributed to L Kopper.

At least 91 records · Page 5Linked to original sources
PubMed1976

Studies on in vitro carcinogenesis. I. Autoradiographic and biochemical study on the incorporation of labelled methylcholantrene into mouse embryonic cells.

The incorporation of radioactive labelled Methylcholanthrene into CBA/T6T6 mouse embryonic fibroblast cultures was studied by using light and electronmicroscopic autoradiographic and also liquid scintillation counting techniques. During 24 hrs treatment time at the applied Methylcholanthrene concentrations (0.01-2.5 mug/ml) the proportion of cells labelled with 3H-Methylcholanthrene and the number of grains above the cells showed a relationship with the duration of treatment and also with the doses. Up to 24 hrs all cells were labelled after treatment with 2.5 mug/ml whereas at 0.01 and at 0.1 mug/ml concentrations Methylcholanthrene could have been detected only 2 and 10% of the cell population resp. The presented results suggested that labelling index reached saturation level earlier than the average number of grains. Electronmicroscopic autoradiography revealed a rather even distribution of grains and there were no signs for preferential binding site of Methylcholanthrene. Biochemical separation showed that 59 and 44% of the radioactivity was bound to macromolecules at 1 and 24 hrs after commencing treatment resp.

Animals↗
PubMed1976

Incorporation of 3H-dibromodulcitol and 3H-dianhydrodulcitol into ascites tumor cells. Autoradiographic study.

The incorporation of 3H-Dibromodulcitol and 3H-Dianhydrodulcitol into S37 ascites tumor cells has been studied with autoradiography. Both drugs war incorporated very rapidly into the cells. The labeling of nucleus was higher than that of cytoplasm. A slight accumulation of grains was found above the condensed chromatin and along the membranes. The uptake of DAD has been more intensive than that of DBD.

Animals↗
PubMed1975

The therapeutic response of three human tumor lines maintained in immune-suppressed mice.

Studies were made of the growth and therapeutic response of three lines of human tumor serially transplanted in immune-suppressed mice. They included a well-differentiated colonic carcinoma (HX 13), a poorly differentiated colonic carcinoma (HX 18), and undifferentiated small-cell carcinoma of the bronchus (HX 29). Their histological appearance and growth rates were stable, with volume-doubling times ranging from 6 to 12 days. Studies by the technique of labeled mitoses showed that the growth kinetics of the three tumor lines were very similar, with median intermitotic times in the range of 26 to 35 hr. An analysis of the incidence of single and double takes revealed evidence for variation in susceptibility among the recipient mice. One tumor (HX 18) was transplantable with single-cell suspensions but 10(5) cells were required for 50 percent takes. The response of the tumors to a range of chemotherapeutic agents was studied. There was evidence that drugs that are known to be effective in the treatment of patients did well, in particular 5-fluorouracil against the colonic tumors and cyclophosphamide against the bronchial carcinoma. Long-term regressions induced by cyclophosphamide in the bronchial carcinoma may reflect assistance from host defense mechanisms.

Animals↗
PubMedDate not supplied

Comparative study on Lewis lung tumor lines with 'low' and 'high' metastatic capacity. II. Cytochemical and biochemical evidence for differences in glycosaminoglycans.

The enhanced metastatic capacity of an in vivo selected Lewis lung tumor line (LLT-HH) was correlated with changes in cell-associated glycosaminoglycans (GAG) using ultrastructural cytochemistry, flow cytometry and biochemistry. The increase in highly sulphated GAG content on the cell membrane of LLT-HH cells compared to the parent LLT cells was demonstrated cytochemically. Using in vitro [3H]glucosamine labelling of GAG components it was shown that the LLT-HH cells were characterized by a high production of heparan sulphate while the parent LLT line had a high hyaluronic acid-chondroitin sulphate production. The high metastatic phenotype is accompanied by an altered production of cell-associated GAGs.

Animals↗
PubMedDate not supplied

Chemotherapeutic sensitivity of liver metastases from intrasplenically-growing Lewis lung tumor.

A recently developed metastatic tumor model was used to study the therapeutic response of liver metastases derived from intrasplenically growing LLT. Treatment was performed on the day following surgical removal of the 'primary tumor'. The life-span of tumor-bearing animals and the number and volume of liver metastases were measured. Cyclophosphamide and 13324 (a new bifunctional nitrosoureido derivative) proved to be most effective. Some other drugs (5-FU, MeCCNU, Lycurim) showed a temporary regression in the formation of macrometastases without influencing the life-span. Adriamycin was slightly more effective given i.p. than i.v.

Animals↗
PubMedDate not supplied

Syndecan-1-dependent homotypic cell adhesion in HT58 lymphoma cells.

OBJECTIVES: Many cellular functions are controlled by cell-cell and cell-matrix interactions. It has recently been found that syndecans, transmembrane heparan sulphate (HS) proteoglycans, can act as receptors or co-receptors and modulate cell adhesion. Our aim was to study the role of syndecan-1 in the aggregation of human lymphoma cells, and to investigate its effect on cell survival. METHODS: Immunocytochemistry, confocal laser scanning microscopy, flow cytometry and aggregation/reaggregation bio-assays were used on HT58, BL41/95 and Raji lymphoma cell lines. RESULTS: Bio-assays showed that the aggregation of HT58 cells was inhibited by heparin, HS, removal of the HS chain and binding of the anti-syndecan-1 monoclonal antibody. In the search for a counter-receptor of syndecan-1, several adhesion molecules were tested, but none of them proved to be the adhesion partner. In the case of heparitinase/trypsin digestion with long-term inhibition of HS synthesis (sodium chlorate treatment), the inhibited aggregation was accompanied by cell cycle arrest and the induction of apoptosis. CONCLUSIONS: The results obtained showed that surface syndecan-1 expression contributes to homotypic adhesion. In addition, HS chains, including those on syndecan-1, take part in the regulation of cell proliferation and active cell death in HT58 lymphoma cells.

Apoptosis↗
PubMedDate not supplied

Syndecan-1 expression in different soft tissue tumours.

BACKGROUND: In vitro studies have suggested that expression of syndecan-1 (CD138) is correlated with morphologic phenotype (epithelioid or spindle) of cultured tumour cells. MATERIALS AND METHODS: Fifty-seven different soft tissue tumours were selected to analyse their syndecan-1 (CD138) reactivity. Immunohistochemical staining of paraffin sections, following a high temperature unmasking technique, was performed. The intensity and the pattern of staining was studied. RESULTS: Cell membrane positivity was observed in epithelioid sarcomas and epithelial elements of synovial sarcomas. GISTs, some malignant epithelioid schwannoma and some fibromatosis showed intracytoplasmatic reaction, while pyogenic granuloma, Kaposi's sarcoma, fibrosarcoma and dermatofibrosarcoma protuberans were negative. CONCLUSION: At first it seemed that the cell membrane positivity of syndecan-1 accompanied true epithelial differentiation in soft tissue sarcomas, but the results further highlighted the non specific nature of this expression. Therefore the heterogeneity in the appearance of syndecan-1 in various soft tissue tumours is not simply associated with the phenotype, suggesting more complex functions.

Dermatofibrosarcoma↗
PubMedDate not supplied

TGF beta 1 induces caspase-dependent but death-receptor independent apoptosis in lymphoid cells.

Transforming growth factor beta 1 (TGF beta 1) is an antiproliferative and proapoptotic cytokine for normal B-cells, however many B-cell lymphomas have lost their response to TGF beta 1. The aim of this study was to identify the sequence of events in apoptosis induced by TGF beta 1 in an EBV negative, human B-cell lymphoma line (HT58). The proportion of apoptotic cells increased gradually (up to 72 hr) at an optimal dose range of 0.5-1.0 ng/ml. The induced cell death required the action of downstream caspases. Caspase activation was accompanied by an increase in the permeability of mitochondrial membranes, but there was no change in the expression of certain members of Bcl-2 family (Bcl-2, Bax, Bcl-XL). Similarly, none of the death receptors or ligands were involved in apoptosis induction. Further study will include the participation of TGF beta 1 target genes in the pore formation of mitochondrial membranes and/or the elimination of a putative survival signal.

Apoptosis↗