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J Lotem

Publications and source records attributed to J Lotem.

76 records · Page 5Linked to original sources
PubMed1975

Induction of specific changes in the surface membrane of myeloid leukemic cells by steroid hormones.

Normal mature macrophages and granulocytes have surface membrane receptors for specific immunoglobulin and immunoglobulin complement, which can be detected by rosette formation with erythrocytes coated with antibody (EA) or with antibody and complement (EAC). There are three types of myeloid leukemia cells, IR-+D-+, IR-+D-minus and IR-minus D-minus. IR-+D-+ cells were induced to form receptors for EAC but not- for EA by the steroid hormones prednisolone, dexamethasone and estradiol. Induction required protein synthesis and was not inhibited by cordycepin or vinblastine. Optimum induction required the continued presence of the hormones. IR-+D-+ cells were also induced by these hormones to migrate in agar, attach to the surface of a Petri dish and form macrophages. IR-+D-minus cells showed a lower inducibility by these hormones and no formation of macrophages. There was no induction of any of these changes with IR-minusD-minus cells. The steroid hormones progesterone, testosterone and cortisone did not induce these changes in any of the leukemic cells and inhibited induction by prednisolone, dexamethasone and estradiol. The results indicate that specific surface membrane changes in myeloid leukemic cells can be induced by certain steroid hormones.

Animals↗
PubMed1975

Control of normal differentiation of myeloid leukemic cells. VI. Inhibition of cell multiplication and the formation of macrophages.

D+ but not D- myeloid leukemic cells can be induced by the appropriate conditioned medium or by serum from endotoxin treated mice, to undergo cell migration in agar, cell attachment to the surface of a Petri dish and differentiation to mature macrophages and granulocytes. Inhibition of cell multiplication by cytosine arabinoside, hydroxyurea, mitomycin C, thymidine, 5-bromodeoxyuridine, 5-iododeoxyuridine, 5-fluorodeoxyuridine or actinomycin D, but not by vinblastine or cycloheximide, induced cell migration, cell attachment to the Petri dish and the formation of macrophages in D+ cells. There was no induction of cell migration or formation of macrophages and a much lower induction of cell attachment in D- cells. The induction of these changes in D+ cells required protein synthesis and the inhibitors showed the same toxicity for D+ and D- cells. The results indicate, that the inhibitors induced specific surface membrane changes in D+ but not in D- cells.

Animals↗
PubMed1974

Different blocks in the differentiation of myeloid leukemic cells.

Some clones of mouse myeloid leukemic cells (D(+)) can be induced to undergo cell differentiation to mature macrophages and granulocytes, and other clones (D(-)) could not be induced to differentiate to mature cells. Normal mature macrophages and granulocytes have surface receptors that form rosettes with erythrocytes coated with specific immunoglobulin or immunoglobulin-complement. The D(+) clones were induced to form receptors by prednisolone, cytosine-arabinoside, 5-iododeoxyuridine, actinomycin D, or serum from mice injected with endotoxin. All these compounds thus induced a common change in the cell surface membrane. The induction of receptors required protein synthesis, and receptors were formed before the appearance of mature cells. There were two types of D(-) clones. One type was induced by these compounds to form receptors, although with a lower inducibility than D(+) clones; in the other type there was no induction of receptors. The results indicate that there are different blocks in the differentiation of myeloid leukemic cells. Some leukemic cells (IR(+)D(+)) can be induced to form receptors and to differentiate to mature cells; others (IR(+)D(-)) can form receptors but not mature cells; and a third type (IR(-)D(-)) could not be induced to form receptors or mature cells.

Animals↗