Akira Oguro

Up-Regulation of Inducible Nitric Oxide (NO) Synthase and NO Production in HL-60 Cells Stimulated to Differentiate by Phorbol 12-Myristate 13-Acetate Plus 1,25-Dihydroxyvitamin D3 Is Not Obtained With Dimethylsulfoxide Plus 1,25-Dihydroxyvitamin D3

Abstract. In previous studies we found that the calciotropic hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] augments the action of either prostaglandin E1 (PGE1) or NaF to induce differentiation of human promyelocytic HL-60 cells, a process that features increased generation of nitric oxide (NO) via up-regulation of inducible nitric oxide synthase (iNOS). We have now examined the short-term interaction of 1,25(OH)2D3 with phorbol 12-myristate 13-acetate (PMA) and dimethylsulfoxide (DMSO) in these cells. PMA (100 nM) alone generally up-regulated several classical indices of macrophagic differentiation and stimulated cellular production of interleukin (IL)-1α, IL-6, tumor-necrosis factor (TNF)-α, PGE2, and NO. Increased generation of NO primarily resulted from increased expression of cellular iNOS. When 1,25(OH)2D3 (10 nM) was added to PMA treatments, most PMA-induced changes, particularly its effects to up-regulate iNOS-dependent NO production and change cell morphology, were multiplicatively augmented. In contrast, DMSO (1.3%) alone, an inducer of granulocytic differentiation, increased cytokine production, but failed to stimulate NO production or induce iNOS. In contrast to its striking interaction with PMA, 1,25(OH)2D3 could not augment DMSOs differentiative effects. Changes in cellular cytokine production were eliminated as the driving force in HL-60 differentiation when specific neutralizing antibodies failed to produce any attenuation of iNOS up-regulation or of the shifts in cell morphology. However, indomethacin (30 μM) blocked the synergistic interaction between 1,25(OH)2D3+ PMA to shift cell morphology and stimulate NO production. Subsequently adding PGE2 (1 ng/ml) to indomethacin-treated cells restored the ability of 1,25(OH)2D3+ PMA to interactively increase cellular NO production, but failed to fully replicate the strong shift in cell morphology typical of PMA + 1,25(OH)2D3 treatments. Our findings suggest that interaction between 1,25(OH)2D3 and PMA to induce macrophagic differentiation increases iNOS-dependent NO production by a mechanism involving a cyclooxygenase product(s), possibly PGE2.

A long-term epidemiological study of dental caries prevalence in institutionalized mentally retarded individuals. Length of stay and DMFT index.

Epidemiological analyses in connection with DMFT index and length of stay were performed on 948 subjects receiving further dental examinations beyond an initial admission examination among 1107 mentally retarded individuals who were admitted to the Niigata Prefectural Institute of Total Training for the Mentally Retarded, Colony Niigata Shiroiwa-no-Sato during the years 1971-1988.(1) The 948 subjects were distributed into 3 groups based on the length of stay, i. e., 1-5, 6-10, and 11 years and longer. The DMFT index showed a tendency of increasing with age in all 3 groups. The DT index showed values blow 2.46 in 15-year-olds and over, and decreased in longer stays. The FT index in all of the 3 groups classified by length of stay was in the range of 3.31-7.60 in almost all age groups (over 15 years of age). The MT index was 1.66-3.17 in 20-24-year-olds and 2.00-11.00 for subjects in their 40s in all of the 3 groups classified by length of stay.(2) In the DMFT index by sex in 1971-1975 newcomers, females had a higher index than males, and it was the same in 1976-1981. This difference may disappear as the length of stay increased, and the difference in the MT index by sex, also higher in females, was gone within 5 years of admission. The difference in the DMFT index by sex in 1976-1981 newcomers disappeared within 5 years. No difference was noted afterwards in 1982-1988 newcomers.(3) While the DMFT index remained stable, a decrease in the DT index and a corresponding increase in the FT index was seen in females as the length of stay increased. In males the DMFT index was raised by an increase in the FT index as the length of stay increased.However, this increase in the FT index immediately after admission in males was accompanied by gradual decreases in the DT and MT indices and consequently by a decrease in the DMFT index in 1971-1975 newcomers when they stayed longer than 6 years, as compared to the data of 1977-1988 admissions as a control.