Spontaneous fusion and nonclonal growth of adult neural stem cells

Multipotent neural stem cells (NSCs) can be isolated from various regions of the adult brain and propagated in vitro. Recent reports have suggested spontaneous fusion events among NSCs when grown as free-floating neurospheres that may affect the genetic composition of NSC cultures. We used adult NSCs expressing either red fluorescent protein (RFP) or green fluorescent protein (GFP) to analyze the fusion frequency of rat and mouse NSCs. Fluorescence-activated cell sorting (FACS) revealed that, under proliferating conditions, approximately 0.2% of rat and mouse NSCs coexpressed RFP and GFP irrespective of whether the cells were grown as neurospheres (mouse NSCs) or as attached monolayers (rat and mouse NSCs). Fused cells did not proliferate and could not be propagated, suggesting that aberrantly fused cells are not viable. Furthermore, we found that neither neurospheres nor monolayers grew clonally, because even very low-density cultures had spheres containing both GFP- and RFP-expressing cells and monolayer patches with GFP- and RFP-expressing cells in close proximity. The nonclonal growth between distinct NSC populations strongly suggests the use of careful and precise culture conditions, such as single-cell assays, to characterize potency and growth of NSCs in vitro.     

Effect of intravenous dextran 70 and pneumatic leg compression on incidence of postoperative pulmonary embolism.

The incidence of pulmonary embolism and deep vein thrombosis was measured in 50 matched pairs of patients undergoing common surgical procedures with preoperative and postoperative ventilation-perfusion lung scans and the fibrinogen uptake test. One patient in each pair was treated with intravenous dextran 70 and pneumatic leggings. The incidence of pulmonary embolism among the treated patients was significantly reduced from 24% to 8%, but the incidence of deep vein thrombosis was not significantly reduced (34% to 24%).     

Venous lipodermatosclerosis: treatment by fibrinolytic enhancement and elastic compression

The value of fibrinolytic enhancement with an anabolic steroid (stanozolol) combined with elastic stockings in treating venous lipodermatosclerosis was assessed in a six-month double-blind cross-over trial. Thirty-four legs of 23 patients in whom other treatments had failed were studied. The patients were randomly divided into two groups who were treated with either stanozolol plus elastic stockings or placebo plus elastic stockings for three months, and then vice versa. Treatment with or without stanozolol caused the area of lipodermatosclerosis to decrease, but the rate of healing when patients took stanozolol was double that when they took the placebo, and this was assumed to be biologically important. Stanozolol also reduced the incidence of extravascular fibrin detected in skin biopsy specimens. The elastic stocking with placebo produced significant decreases in leg volume, ankle circumference, and skin thickness. Stanozolol is valuable in treating intractable lipodermatosclerosis, giving relief of pain and reducing induration, inflammation, tenderness, and pigmentation.