The direct effect of hypoxia and the effect of hypoxic endothelial cells conditioned medium on cultured pulmonary arterial smooth muscle cells in vitro were studied with phase contrast microscopy,3H-thymidine labelled technique and flow cytometric measurements. The results showed that direct hypoxia inhibited proliferation of pulmonary arterial smooth muscle cells, retained pulmonary arterial smooth muscle cells in the Go/G1 phase and decreased3H-thymidine incorporation into pulmonary arterial smooth muscle cells and that hypoxic endothelial cells conditioned medium stimulated proliferation of pulmonary arterial smooth muscle cells, promoted pulmonary arterial smooth muscle cells from G0/G1 phase to S phase and increased3H-thymidine incorporation into pulmonary arterial smooth muscle cells. It was reasonable to believe that hypoxia might enable pulmonary arterial endothelial cells to secrete some growth factors which could stimulate proliferation of pulmonary arterial smooth muscle cells, thereby playing an important role in structural remodeling of the pulmonary arteries and in the development of hypoxic pulmonary hypertension.
Human embryos after 3–4.5 months of gestation were obtained with abortion. The brain tissue of the bodies was scissored up to obtain 1–3 mm3 pieces, and 7% dymethyl sulfoxide (DMSO), as a cryoprotectant, was added, and then stored at −70°C for 1–30 days or at −196°C for 1–84 days. The survival rate of stored cells was 64%–88%. During 6 days of storage with neuron culture medium, the survival rate of cells at 4°C is over 50% each day, but, as time goes on, the count of the cells is getting less and less. The cells washed out DMSO after cryopreservation and the planting fresh cells can adhere to the wall of the culture bottle, grow, display various forms of neurons and gliacytes. From the above findings, it was suggested that: 1) The fetal human brain tissue, handled properly, can endure cryopreservation with7% DMSO as a cryoprotective agent; 2) The storage time was related insignificantly to the survival rate of the tissues stored; 3)It is available for a short proservation at 4°C and 4) It is possible to set up a bank of fetal human brain tissue.