Kiyoshige Ochi

Bio: Kiyoshige Ochi is an academic researcher from Chugai Pharmaceutical Co.. The author has contributed to research in topics: Alkyl & Derivative (chemistry). The author has an hindex of 13, co-authored 65 publications receiving 653 citations.

Vitamin D3 derivatives having a substituent at 2-position

Abstract: A 1α-hydroxy vitamin D3 derivative of the formula: ##STR1## where R1 is a hydroxyl group, an amino group or the group: OR' (where R' is a lower alkyl group having 1 to 7 carbon atoms that may or may not be substituted by a hydroxyl group, a halogen atom, a cyano group, a lower alkoxy group having 1 to 3 carbon atoms, an amino group, or an acylamino group); R2 is a hydrogen atom or a hydroxyl group), and a process for preparing the same are disclosed. The compound represented by the formula above has the calcium control action and the ability to induce differentiation in tumor cells and, therefore, are useful as an antitumor agents and a medicine for treating calcium dysbolism-caused diseases.

Synthetic studies of vitamin D analogues. XIV. Synthesis and calcium regulating activity of vitamin D3 analogues bearing a hydroxyalkoxy group at the 2 beta-position.

Abstract: Four vitamin D3 analogues (7a, 7b, 7c and 7d) bearing a hydroxyalkoxy group at the 2β-position were synthesized from the α-epoxide (5). The C-3 analogue (7b) showed the highest potency for elevating plasma calcium levels in rats. Furthermore, the 25-hydroxylated C-3 analogue (ED-71) (3), prepared from the 25-hydroxylated α-epoxide (9), significantly increased plasma calcium to levels much higher than those in rats administered 1α, 25-(OH)2-D3 (1).

Heat-induced aggregation of recombinant erythropoietin in the intact and deglycosylated states as monitored by gel permeation chromatography combined with a low-angle laser light scattering technique.

Abstract: Aggregate formation of recombinant human erythropoietin (r-EPO) on heat-treatment was followed by gel permeation chromatography combined with a low-angle laser light scattering technique under various conditions with respect to pH and salt concentration in order to provide basic knowledge about the change strictly required to be monitored for medicinal proteins. When heated at 60 degrees C at neutral pH, an aggregate with a limited size consisting of about 20 r-EPO molecules was formed. On heating at 50 degrees C at acidic pH, aggregation was unlimited. The aggregation proceeded non-covalently in acidic pH, but in alkaline pH covalent bond formation was also involved. Increase in salt concentration enhanced the aggregation. Deglycosylation of the N-linked oligosaccharides made r-EPO remarkably susceptible to aggregation on heat-treatment, indicating that the carbohydrate chains are essential to the stability of r-EPO.

Differentiation of mouse myeloid leukemia cells induced by 1 alpha,25-dihydroxyvitamin D3

Abstract: Mouse myeloid leukemia cells can be induced to differentiate into macrophages in vitro by 1 alpha,25-dihydroxyvitamin D3, the active form of vitamin D3. The minimal concentration of 1 alpha,25-dihydroxyvitamin D3 to induce the cell differentiation was 0.12 nM. The degree of cell differentiation in various markers induced by 12 nM 1 alpha,25-dihydroxyvitamin D3 was nearly equivalent to that induced by 1 microM dexamethasone, the most potent known stimulator. Among several markers of the differentiation by 1 alpha,25-dihydroxyvitamin D3, phagocytic activity was induced within 24 hr, and this was followed by induction of lysozyme and locomotive activities. Similar changes were also induced by 0.01-1 microM 1 alpha-hydroxyvitamin D3. 25-Hydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3 showed only weak inducing activity. These results suggest the possibility that, in addition to its wellknown biological activities in enhancing intestinal calcium transport and bone mineral mobilization, 1 alpha, 25-dihydroxyvitamin D3 is involved in the differentiation of bone marrow cells.