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R J Scheper

Publications and source records attributed to R J Scheper.

294 records · Page 17Linked to original sources
PubMed1975

Non-specific and DNP--erythrocyte rosette formation after contact sensitization with DNCB.

DNA--guinea-pig erythrocyte rosette-forming cells (RFC), as found after contact sensitization of guinea-pigs with DNCB, were shown to be highly sensitive to pretreatment with cyclophosphamide or X-irradiation, which suggests that these cells are B cells. The finding was confirmed by rosette-blocking experiments using an anti-immunoglobulin serum. It has already been shown that they are not directly related to antibody production. Possibly they represent precursors of antibody-producing cells. An increase in rosette formation, using non-antigenically related erythrocytes, was shown to parallel development of cell-mediated immunity (CMI) in the lymph nodes. These non-specifically induced RFC were also found to be B cells. Data were obtained which make it improbable that either proliferation or influx of B cells during development of CMI plays a major role in this increase. An alternative mechanism is suggested, while a possible role for these non-specifically induced RC is proposed.

Animals↗
PubMedDate not supplied

c-Ha-ras transfection and expression of MDR-related genes in MCF-10A human breast cell line.

BACKGROUND: We studied the relationship between ras transfection and the drug resistance phenotype in the MCF-10A cell line (a non-transformed immortalized human breast epithelial cell line). MATERIALS AND METHODS: Parental (MCF-10A) and c-Ha-ras transfected (MCF-10A H) cell lines were tested for resistance to Doxorubicin, Maphosphamide and Cisplatinum, by evaluating the inhibition of [3H]-thymidine incorporation. Cells were also examined for the expression of different resistance mechanisms by immunocytochemical and RT-PCR methods. RESULTS: ras-transfected cells were much more resistant to Cis-platinum than parental ones. GST-pi the GST isoenzyme frequently involved in human cancers) increased only in transfected cells. No expression of any other resistance mechanisms (MDR, MRP, LRP) was found by immunocytochemistry either in parental or in transfected cells; nevertheless, the more sensitive RT-PCR tests detected mrp products in parental and in transfected cells: gene expression levels were low and equivalent in both cell lines. CONCLUSIONS: ras transfection can induce resistance to Cis-platinum by increasing GST-pi expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Expression analysis of protein kinase C isozymes and multidrug resistance associated genes in ovarian cancer cells.

We recently demonstrated a correlation between the expression levels of the PKC eta isozyme and the MDR1 or MRP genes in blasts from AML patients, and in primary breast cancers. In order to extend these findings we analysed ovarian cancer cells from 14 ascites aspirates from 8 patients using a cDNA-PCR approach. 5 patients were examined in follow up studies. 4 out of these 5 patients received continuous chemotherapy. The relative increases in MDR1, MRP, LRP or PKC eta mRNA expression levels were monitored. In one of these patients combined significant increase in MDR1, MRP, LRP and PKC was seen. One follow up sample was obtained after chemotherapy was discontinued. In this case significant relative decreases of MDR1, LRP and PKC eta mRNA expression levels were found. Furthermore, a significant positive correlation was determined for the relative mRNA expression levels of MRP and PKC eta. These results point to a multifactorial emergence of MDR in this type of tumor with a possible involvement of the PKC eta isozyme.

ATP Binding Cassette Transporter, Subfamily B, Mem↗