We have established a multipotent clonal cell line, named MEB5, from embryonic mouse forebrains after the infection of a retrovirus carrying E7 oncogene of human papillomavirus type 16. MEB5 cells proliferated in serum-free, epidermal growth factor (EGF)-supplemented medium. They expressed markers for neural precursor cells (nestin, A2B5, and RC1) and did not express markers for neurons (class III beta-tubulin), astrocytes (glial fibrillary acidic protein), and oligodendrocytes (galactocerebroside). MEB5 cells were stably maintained in an undifferentiated state with a diploid karyotype in the presence of EGF. When they were deprived of EGF, about 50% of the cells died due to apoptosis within 24 h. The remaining cells differentiated into neurons, astrocytes, or oligodendrocytes within 2 wk. The newly developed cells with neuronal morphology were immunoreactive for gamma-aminobutyric acid and exhibited neuronal electrophysiological properties. When MEB5 cells were treated with leukemia inhibitory factor for 7 d, they were induced to differentiate exclusively into astrocytes. These results indicate that MEB5 is a cell line with characteristics of EGF-dependent, multipotent neural precursor cells. This cell line should provide a good model system to study the mechanisms of survival, proliferation, and differentiation of the multipotent precursor cells in the central nervous system.

Animals↗

PubMedDate not supplied

Effect of ipriflavone on bone in elderly hemiplegic stroke patients with hypovitaminosis D.

A significant reduction in bone mineral density occurs in stroke patients on the hemiplegic side, correlating with the degree of paralysis and vitamin D deficiency due to malnutrition, sunlight deprivation, and immobilization-induced hypercalcemia, and increases the risk of hip fracture. We evaluated the effect of ipriflavone and 1alpha-hydroxyvitamin D3 [1alpha(OH)D3; vitamin D3] administration on bone mineral density preservation as compared with untreated controls. In a randomized and prospective study of 103 patients with hemiplegia after stroke (the mean duration of illness was 4.8 yr), 68 (34 patients in each group) were given 600 mg ipriflavone or 1 microg vitamin D3 daily for 12 mo, whereas the remaining 35 patients received no drug. Bone mineral density on the hemiplegic side decreased by 1.4% in the ipriflavone group, 3.8% in the vitamin D3 group, and 5.4% in the control group (P < .0001, ipriflavone v vitamin D3 and control). At baseline, all three groups of patients showed a 25-hydroxyvitamin D insufficiency, increased serum ionized calcium, and low levels of 1, 25-dihydroxyvitamin D, suggesting immobilization-induced hypercalcemia and inhibition of renal synthesis of 1, 25-dihydroxyvitamin D. After treatment, the serum 1, 25-dihydroxyvitamin D level increased by 139.9% in the ipriflavone group and by 26.9% in the vitamin D3 group. Significant decreases in the serum ionized calcium and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen, and increases in parathyroid hormone and bone Gla protein were observed in the ipriflavone group, whereas no changes occurred in the other two groups. One patient in the untreated group suffered a hip fracture, compared with none in the ipriflavone and vitamin D3 groups. These results suggest that ipriflavone is more efficacious than vitamin D3 in the prevention of decreased bone mineral density in hemiplegic stroke patients because it decreases serum calcium levels through inhibition of bone resorption and cause a subsequent increase in 1, 25-dihydroxyvitamin D concentration.

Absorptiometry, Photon↗