Hematopoietic stem cell differentiation occurs in direct proximity to osteoblasts within the bone marrow cavity. Despite this striking affiliation, surprisingly little is known about the precise cellular and molecular impact of osteoblasts on the bone marrow microenvironment. Recently, we showed that human osteoblasts produce a variety of cytokine mRNAs including granulocyte colony-stimulating ...

X-irradiation of purified primary cultures of mouse bone marrow stroma or permanent cloned marrow stromal cell lines in plateau phase decreases production of macrophage progenitor cell-specific colony-stimulating factor to a plateau minimum of 40% of control levels after doses of 50 to 500 Gy delivered at 2 Gy/min. After 50 Gy there is increased bioavailability of another growth factor(s) that ...

In this study granulocyte-macrophage colony stimulating factor (CSF) was prepared from rabbit and guinea pig lung tissues. The biological activity of these CSFs was measured on semisolid agar culture and compared with those of mouse and rat. Weight of animals, incubation time and cross-reactivity of CSFs with different bone marrow sources were also investigated. The results showed that both...

Transcription of early growth response gene-1 (Egr-1) is required for macrophage differentiation. Since granulocyte-macrophage colony-stimulating factor (GM-CSF) induces macrophage proliferation as well as the transcription of Egr-1 mRNA, we characterized the induction of Egr-1 protein in murine peritoneal macrophages following treatment with GM-CSF. As determined by Western blot analysis, the ...

Supernatants of cultured human thymic nonlymphoid cells were assayed for granulopoietic factors using cultures of low density bone marrow mononuclear cells (LD-BMMC). Thymic nonlymphoid cell-conditioned medium (TNLC-CM) supported vigorous myeloid colony growth of LD-BMMC. and of LD-BMMC depleted of T lymphocytes and/or monocytes. Colony stimulating activity (CSA) in TNLC-CM was abrogated by a h...

OBJECTIVES To elucidate the potential role of cytokines in the pathogenesis of cardiomyopathy and myocarditis. BACKGROUND Experimental studies show that certain cytokines depress myocardial contractility and that tumour necrosis factor-alpha plays an important part in the pathogenesis of myocardial injury in animal models of viral and autoimmune myocarditis. METHODS Plasma interleukin 1-alp...