BACKGROUND GTPases of the immunity-associated protein family (GIMAPs) are predominantly expressed in mature lymphocytes. Studies of rodents deficient in GIMAP1, GIMAP4, or GIMAP5 have demonstrated that these GTPases regulate lymphocyte survival. In contrast to the other family members, GIMAP8 contains three potential GTP-binding domains (G-domains), a highly unusual feature suggesting a novel f...

Previous studies have established that mature neutrophils from the peritoneal cavity, blood, and bone marrow of beige (Chédiak-Higashi syndrome) mice essentially lack activities of two lysosomal proteinases: elastase and cathepsin G. There are, however, significant levels of each enzyme in early neutrophil precursors in bone marrow. In the present experiments, it was found that the addition of ...

Vessel-like networks are quickly formed in subcutaneous FGF2-supplemented Matrigel plugs by two cell types: NG2(+) pericytes and F4/80(+) macrophages. Although not detected in these networks until 7 days after plug implantation, the appearance of CD31(+) endothelial cells marks the onset of vessel perfusion and the establishment of mature vessel morphology, with endothelial cells invested tight...

Techniques for staining (silver, osmium, metal sulfides, ink) and microphotography (epi-illumination) of polished bone surfaces have been developed to visualize the three-dimensional structure of the shafts of mammalian long bones. Bone is a two-compartment system with capillaries and some kinds of connective tissue in one compartment separated from fibers of bone collagen, often forming lamell...

The importance of cell rigidity in regulating the release of reticulocytes from the bone marrow has been investigated in a model system. Reticulocytes were obtained from phlebotomized rabbits and separated from whole blood by discontinuous density gradient centrifugation. The mechanical properties of the cells were tested. Using single-cell micromechanical techniques, the membrane elastic rigid...

Pro-forms of growth factors have received intensive scientific attention recently because in some cases different biological activities have been ascribed compared with the mature growth factors. Examples are the pro-apoptotic role of the nerve growth factor (NGF) proform (proNGF) or the latency of the transforming growth factor (TGF)-beta pro-form (proTGF-beta). To investigate a possible biolo...

The requirement for new bone to replace or restore the function of traumatised, damaged, or lost bone is a major clinical and socioeconomic need. Bone formation strategies, although attractive, have yet to yield functional and mechanically competent bone. Bone tissue engineering has been heralded as the alternative strategy to regenerate bone. In essence, the discipline aims to combine progenit...

We describe the effects of the overexpression of noggin, a bone morphogenetic protein (BMP) inhibitor, on osteoblast differentiation and bone formation. Cells of the osteoblast and chondrocyte lineages, as well as bone marrow macrophages, showed intense beta-gal histo- or cytostaining in adult noggin+/- mice that had a LacZ transgene inserted at the site of noggin deletion. Despite identical BM...

Osteogenesis imperfecta (OI or brittle bone disease) is a disorder of connective tissues caused by mutations in the collagen genes. We previously showed that intrauterine transplantation of human blood fetal stem/stromal cells in OI mice (oim) resulted in a significant reduction of bone fracture. This work examines the cellular mechanisms and mechanical bone modifications underlying these thera...

The integrity of the skeleton depends upon bone remodeling, the permanent and controlled resorption of bone by osteoclasts (OC) and its subsequent replacement by bone-forming osteoblasts. An imbalance between bone resorption and bone formation results in osteoporosis (if bone resorption exceeds bone formation) or osteopetrosis (if bone formation exceeds bone resorption). The regulation of the b...