Biomedical subjects

L Pasternak

Publications and source records attributed to L Pasternak.

17 recordsLinked to original sources

PubMed1994

Persistence of bcr-abl mRNA-expressing cells in long-term cultures established from chronic myeloid leukemic bone marrow or blood.

Long-term cultures (LTC) established from chronic myeloid leukemic (CML) bone marrow or blood contain bcr-abl mRNA-expressing cells, as demonstrated by the polymerase chain reaction (PCR). Bcr-abl sequences were detectable in cultures from all of nine patients investigated. In LTC from two patients, in which a cytogenetic conversion from Ph+ to Ph- was noted at day 20 and 40, respectively, the PCR for bcr-abl remained positive, at least up to day 112 and 245, respectively, in vitro. The differences between the results of cytogenetic and PCR analyses was explained by the fact that the metaphases studied were obviously derived from spontaneously EBV-transformed bcr-abl mRNA-negative B cells, which may become the dominating cell type very early in LTC from bone marrow or blood. LTCs cloned for EBV-transformed B cells which no longer harbor admixed macrophages are bcr-abl mRNA negative. In conclusion, bcr-abl mRNA-expressing cells may show long-term persistence in LTC established from CML bone marrow or blood.

Adult↗

PubMed1994

Behavior in vitro of long-term cultured bone marrow or blood cells from chronic myeloid leukemia: adhesion molecules and differentiation antigens as detected by immunocytochemistry.

Long-term cultures (LTC) were established from chronic myeloid leukemic bone marrow or blood. As detected by immunocytochemistry using 25 different monoclonal antibodies, the in vitro cultured cells express a variety of adhesion molecules and differentiation antigens. beta 1 and beta 2 integrins are constantly present on long-term cultured cells. CD4, CD54, CD58, and CD71 markers become highly expressed on the cells after about 10 days in vitro while CD56 is permanently lacking. Only 5 of the 17 patients studied had between 25 and 85 per cent CD33 and CD34 differentiation antigen-positive cells initially in the bone marrow or blood. There was a decrease to less than 10 per cent after six to eight weeks in culture. In later stages of long-term culture, monocytes/macrophages become the dominating cell types. Blast cells are admixed to these cells in varying numbers. In 4 of the 17 cases studied long-term cultures converted to cell lines showing indefinite cell growth. The cells were identified as B cell blasts spontaneously transformed by Epstein Barr virus (EBV). The permanent myeloid and monocytic leukemia cell lines K-562, HL-60, KG-1, RC-2a, CTV-1, THP-1, and U-937 were likewise tested for adhesion molecules and differentiation antigens. A stable marker expression was found, the pattern of which is characteristic of each cell line. CD4 is frequently present on myeloid and monocytic leukemia cell lines (HL-60, RC-2a, THP-1, and U-937). Exceptionally, CD2 and CD34 were shown on KG-1. CD49e, CD49f, CD44, and CD71 are expressed on all cell lines tested.

Antigens, CD↗

PubMed1988

Direct comparison of electric field-mediated and PEG-mediated cell fusion for the generation of antibody producing hybridomas.

As an alternative to polyethylene glycol (PEG), electric field pulses offer, in theory, fusion conditions whose parameters are better controllable. In 1985 (1) we reported on the successful generation of hybridoma clones by means of electrofusion performed in a batch-type manner similar to that usually employed with PEG, and applicable to any type of antigens. Here we summarize the results of a series of fusions performed since then in which both electric field and PEG induced fusion were directly compared. Different types of antigens were used. Electrofusion resulted in a 3.8 to 33.0 times higher yield of hybridomas per unit number of spleen cells. Moreover, hybridomas grew more vigorously after fusion and, therefore, were earlier visible. Other parameters examined revealed no differences between hybridomas generated by either method.

Animals↗

PubMed1985

[Transplantation immunity to a UV-induced murine sarcoma by injection of a glycoprotein fraction from the tumor].

One single subcutaneous injection of 100 micrograms protein of a glycoprotein fraction from UV light-induced mouse sarcoma produces transplantation resistance against the same tumor. The glycoprotein fraction was isolated by 2% Triton X-100 and 3M KCl from enriched membranes. As measured by immunogenicity a tenfold enrichment of a tumor-associated antigen was obtained when compared with the 3M KCl extract on the basis of protein concentration.

Animals↗

PubMed1980