Faculty Bibliography

Basic fibroblast growth factor (bFGF) is a potent mitogen for human bone marrow stromal cells and stimulates haematopoiesis in vitro. We report here that primary human bone marrow cultures contain bFGF and express heparin-like bFGF binding sites on the cell surface and in the extracellular matrix (ECM). bFGF bound predominantly to a 200-kD cell surface heparan sulfate proteoglycan (HSPG), which was also found in conditioned medium. bFGF was released from bone marrow cultures by incubation with phosphatidylinositol-specific phospholipase C (PI-PLC) and, less efficiently, by plasmin. Solubilized bFGF was found as a complex with the 200-kD HSPG. The complex was biologically active as shown by its ability to stimulate plasminogen activator production in bovine aortic endothelial cells. bFGF-HSPG complexes of bovine endothelial cells, however, were not released by PI-PLC. While only trace amounts of the bFGF-binding 200-kD HSPG were released spontaneously from bone marrow cultures, incubation with PI-PLC solubilized almost all of the 200-kD HSPG. The HSPG could be metabolically labeled with ethanolamine or palmitate, which was partially removed by treatment with PI-PLC. These findings indicate linkage of the HSPG to the cell surface via a phosphatidylinositol anchor. Plasmin released the 200-kD HSPG less efficiently than PI-PLC. We conclude that HSPGs of human bone marrow serve as a reservoir for bFGF, from which it can be released in a biologically active form via a dual mechanism; one involving a putative endogenous phospholipase, the other involving the proteolytic cascade of plasminogen activation

We previously showed that basic fibroblast growth factor (bFGF) is a potent mitogen for human bone marrow (BM) stromal cells and significantly delays their senescence. In the present study, we demonstrated that low concentrations of bFGF (0.2 to 2 ng/mL) enhance myelopoiesis in long-term human BM culture. Addition of bFGF to long-term BM cultures resulted in an increase in (a) the number of nonadherent cells (sixfold), particularly those of the neutrophil granulocyte series; (b) the number of nonadherent granulocyte colony-stimulating factor (G-CSF)- and granulocyte-macrophage colony-stimulating factor (GM-CSF)-responsive progenitor cells; (c) the number of adherent foci of hematopoietic cells (10-fold); and (d) the number of progenitor cells in the adherent stromal cell layer. These effects were not noted with higher concentrations of bFGF (20 ng/mL). Thus, low concentrations of bFGF effectively augment myelopoiesis in human long-term BM cultures, and bFGF may therefore be a regulator of the hematopoietic system in vitro and in vivo

Nude mice given inoculations s.c. of a human squamous carcinoma--HEp3 (1.5 x 10(6) cells/mouse)--developed invasive tumors that produced high levels of urokinase-type plasminogen activator (uPA) and metastasized predictably to the lungs and lymph nodes of the host. To investigate the role of uPA in invasion and metastasis, mice given inoculations of tumor cells were treated daily with s.c. injections of specific, anti-human uPA antibodies (rabbit polyclonal, 150 inhibitory units; mouse monoclonal, 3000 inhibitory units/mouse/day). Control mice received either saline or preimmune rabbit immunoglobulins. A total of approximately 50 mice was studied. The tumors were surgically excised 10 to 17 days postinoculation when weighing 1 to 2 g. Antibody administration was discontinued after tumor excision. Two strategies were used: (a) following the removal of tumors the mice were maintained and observed until respiratory distress, indicative of lung metastasis, was evident; or (b) their lungs were examined for evidence of metastasis on the day of tumor removal. While histological sections of s.c. tumors excised from control mice indicated extensive local invasion, evidence of invasion was absent in most tumors excised from mice in which tumor uPA was inhibited by the antibody (P less than 0.025). The inhibition of local invasion did not, however, lead to a reduced incidence of distant metastasis. Since we found that the presence of HEp3 tumors in mice elicits a pronounced granulocytosis, we propose that this response may facilitate the spread of tumor cells by a mechanism independent of endogenous tumor proteases

In view of the uncertainty regarding the natural history and management of individuals with the myelodysplastic syndromes, a prospective study of 43 consecutive and previously untreated patients was undertaken in order to identify haematological features that could predict for poor prognosis. A significant correlation between percentage of blasts in the bone marrow, maturity index and the number of cell lineages involved was demonstrated with both the risk of leukaemic transformation and survival. It remains to be determined whether further accumulation of data will result in similar predictive values for karyotypic analysis, in vitro bone marrow culture and the species of plasminogen activator secreted by the cells. Since treatment ranges from red cell transfusion and administration of maturation-inducing agents to aggressive cytotoxic chemotherapy or bone marrow transplantation, the development of predictive models, based on relevant prognostic factors, remains the most rational basis for choices between these various options

Basic fibroblast growth factor (bFGF) is a potent mitogen for human bone marrow stromal cells. Normally, large numbers of human bone marrow stromal cells are difficult to obtain. However, nanogram/ml concentrations of bFGF stimulate the growth of passaged bone marrow stromal cells both in media formulated for optimal growth of stromal cells and in a simple mixture of RPMI-1640 and 10% fetal calf serum facilitating the successive expansion of stromal cells through multiple passages. bFGF also greatly accelerates the formation of a primary stromal cell layer following inoculation of newly harvested bone marrow cells into dishes. In the presence of bFGF, the stromal cells attain high densities, lose their contact inhibition and grow in multilayered sheets. Heparin greatly potentiates the stimulatory effect of low concentrations of bFGF. The effects of bFGF are fully reversible: cells cultured in the presence of this factor for multiple passages revert to normal growth rates following trypsinization and subculture. A short (4 h) exposure of the cells to bFGF elicits profound growth stimulation. This supports the hypothesis that this factor binds to glycosaminoglycans in the cell matrix which act as a storage reservoir for this cytokine

Seventy-two consecutive and previously untreated adults with acute non-lymphoblastic leukaemia (ANLL), having a median age of 36 years (range 12 to 71), were prospectively randomised to receive conventional doses of cytosine arabinoside and doxorubicin combined with either etoposide (CTR III) or 6-thioguanine (DAT). Morbidity was comparable between the two regimens and complete remission (CR) rates of 52% and 62% respectively (p greater than 0.50) were not influenced by age above or below 50 years, initial white cell count, French-American-British classification, or race. However, growth pattern in the GM: CFUc assay was found to identify a subgroup of patients who had a significantly higher CR rate. Similarly, the secretion of tissue plasminogen activator by leukaemic blasts in vitro uniformly predicted for primary drug resistance, whereas a CR rate of 68% was associated with production of the urokinase type or a mixture of both enzymes. Remission duration and survival did not differ between these two forms of chemotherapy, nor were they influenced by immunotherapy with C. parvum or the duration of maintenance therapy, whereas age below 50 and the species of plasminogen activator secreted were significant prognostic factors. It is concluded that etoposide can be substituted for 6-thioguanine in these cytosine arabinoside and doxorubicin-containing regimens and that for both combinations the most sensitive prognostic factor for CR and survival is the species of plasminogen activator secreted in vitro by the leukaemic blasts

The secretion of tissue plasminogen activator (t-PA), urokinase (u-PA) and their inhibitors by the human leukemia cell line K562 was examined. K562 cells normally secrete both t-PA and u-PA in a ratio of 3:1. After addition of 10 or 1 ng/mL phorbol myristate acetate (PMA) to K562 cells, a marked decrease in enzymatic activity is observed in the medium. However, when t-PA antigen rather than activity is measured, an increased amount is found in the medium under these conditions. PMA also induces secretion of the two inhibitors of plasminogen activator: plasminogen activator inhibitor 1 (PAI-1) and plasminogen activator inhibitor 2 (PAI-2). This accounts for the decrease in total enzymatic activity under conditions when production of t-PA antigen is increased. A study of the time course of induction revealed that the synthesis of plasminogen activator occurred before that of its inhibitors. Low concentrations of PMA (0.1 ng/mL) induce t-PA antigen primarily and not the inhibitors. This results in an increase in total enzymatic activity, with 94% of the secreted activity being t-PA. Thus, the secretion of plasminogen activators and their inhibitors can be manipulated in certain leukemic cells by inducers such as PMA

PIP: If you are pregnant and near 40 years old there is 1/137 chance that your child may have Down's syndrome, or 1/65 chance he will have a physical or mental problem. There are tests that can indicate these problems but they increase the risk of spontaneous abortion. A woman should not be forced to carry an unwanted child, and the needs of childless couples should not be addressed in abortion discussions. The Roe v. Wade case made the distinction of not having to determine when life begins, but when it can be sustained outside the body. The Missouri statute states that human life begins at conception, an unborn child has protectable life interests and the parents of that child have protectable life interests of the unborn child in relation to life, health and its well being. States that are really concerned with the interests of unborn children should improve prenatal care, educate teens on contraception, AIDS, and be concerned about violent behavior and smoking. Voters in Michigan and Arkansas approved a law to stop the use of public funds for abortion, other than saving the mother's life. Pro- choice advocates are concerned that the conservative appointees to the supreme court will reverse the previous decision. O

A human melanoma cell line has been established which when inoculated subcutaneously into nude mice, is consistently metastatic. In order to document blood-borne spread, it was necessary to excise the primary tumour so prolonging the life of the animal and allowing metastases to become apparent. Macroscopically detectable metastatic spread at autopsy was reliably indicated by weight loss of the animals. Metastases were widespread and involved the lungs, abdominal cavity and organs and the gonads. The size of the primary tumour at the time of its removal, and not the period of s.c. growth, determined the incidence of metastatic disease. Removal of tumours weighing less than 0.6 g prevented metastasis, whereas all of the animals showed widely disseminated disease if the tumour was allowed to attain a size of 1.6 g before excision