Changes in stored and short-term cultures of mouse bone marrow cells.

Changes in cells of mouse bone marrow cultured for 6--24 hr were followed both when fresh, and after storage for 3 to 5 days at a temperature of +2 to +4 degrees C. Considerable alterations were observed in the morphology, activity and transformation of these cells both during the storage period and the subsequent culture. Phagocyte ability was also detected in these cultures.

The effect of fibrinogen-methotrexate derivatives on HeLa cell growth.

Proteolytic cleavage of bovine fibrinogen with covalently bound methotrexate (MTX) was studied using four different proteolytic enzymes--trypsin, chymotrypsin, pepsin, and cathepsin D and the interaction of the modified fibrinogen (or fibrin) with HeLa cells was investigated. The presence of fibrin-MTX derivative did not induce any significant morphological alternations of cells. The fibrin-MTX derivative in the gel form was solubilized easily by the action of all proteinases investigated, hydrolysis of highly crosslinked denatured fibrin-MTX in suspension proceeded slower. The solubilized fibrin-MTX degradation products had a strong inhibiting effect on the growth of HeLa cells cultured in monolayer indicating the liberation of chemotherapeutically active MTX from its fibrin derivative.

Cultivation and differentiation of haemopoietic CFU-C cells in semisolid medium.

The possibilities of cultivating murine bone marrow in semisolid agar and in methyl cellulose were investigated. The proliferative capacity of the haemopoietic CFU-C stem cells were demonstrated. The growth of CFU-C in fresh murine bone marrow and murine marrow short-term preserved at -75 degrees C was compared. The content of cells capable of proliferation was lower and the onset of colony formation was delayed in preserved bone marrow. Procedures appropriate for routine work were employed for evaluating haemopoietic colonies.

Human placental conditioned medium (from different phase of pregnancy) as a source of colony-stimulating activity for cultures of human and mouse. granulocyte-macrophage colony-forming cells in semisolid agar.

We have investigated the effect of conditioned medium derived from cultures of human placental tissue from different phases of pregnancy on in vitro growth of human and mouse granulocyte-macrophage colony forming cells in semisolid agar. We have confirmed that the colony-stimulating activity of human placental conditioned (normal delivery) medium was equivalent to the activity of peripheral blood leucocyte underlayers when medium was added at a 5%-20% concentration to the semisolid agar. Placentas from the 12th amd 10th week of gestation were found not convenient for preparation of medium with high CSA; the activity of media prepared from their cultures was not significantly higher than the autostimulating activity of bone marrow alone. Human placental conditioned medium proved inconvenient for cultures of mouse GM-CFC in semisolid agar containing foetal calf serum.

Cultivation of frozen mouse bone marrow cells in agar.

The authors attempted to cultivate frozen mouse bone marrow cells in a semisolid medium. They demonstrated that the stem haematopoietic cells of frozen mouse bone marrow were capable of proliferation and of colony formation on agar. The much smaller number of colonies from frozen mouse bone marrow (about 80% fewer) compared with fresh marrow is evidence that part of the stem haematopoietic cell population retains proliferative capacity even after freezing.

Cultivation of fresh and frozen mouse bone marrow. - Application of methyl cellulose.

The culture of cells of both fresh and frozen mouse bone marrow on methyl cellulose (MC) was approached. We used 1.5%-concentration of MC and proved the stem cells of fresh and frozen mouse bone marrow to proliferate and form haemopoietic colonies on MC. We established that the freezing process did not significantly decrease the proliferative capacity of CFU-C stem cells.

[The effect of storage and short term cultivation the proliferation of mouse bone marrow stem cells]. / Der Einfluss von Lagerung und Kurzzeitkultivierung auf die Repopulationsfähigkeit von Stammzellen aus Mäuseknochenmark.

Suspension of stored and short-term cultured murine bone marrow cells was i. v. administered to lethally irradiated mice. We demonstrated that the cells still after 72 h of storing and 24 h of culture in liquid medium were capable of proliferation and on day 9 following transplantation could produce colony forming units in the spleens of lethally irradiated mice. We established the relative participation of individual types of cells in the recovery of haemopoiesis in the spleens.

[Transplantation of bone marrow cells into lethally irradiated mice. Morphology of megakaryocytes]. / Uber die Transplantation von Knochenmarkzellen auf letal bestrahlte Mäuse Morphologie der Megakaryozyten.

We described morphological changes of megakaryocytes in the bone marrow and spleen of lethally irradiated mice, dependent on the time lapse following bone marrow transplantation. The functional active megakaryocytes of various morphological types were found to predominate in the tissues on about day 20 to 25.