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Biomedical subjects

N Kurihara

Publications and source records attributed to N Kurihara.

At least 217 records · Page 12Linked to original sources
PubMed1986

Phagocytosis of different matrix components by different cell types at bone-forming sites in cultured mouse calvariae.

Sites of bone formation on fragments of parietal bone of fetal-mice cultured for 10 days were examined by electron microscopy after addition of either ruthenium red or ferrocyanide to the postfixation fluid. Osteoclasts, osteoblast-like cells, and macrophages were the principal active cells at these formation sites. The mononuclear cells (osteoblast-like cells and macrophages) in the osteoid tissue showed evidence of having incorporated elements of calcified tissue. Osteoblast-like cells had phagocytized collagen fibrils and calcified bone matrix. This occurred more frequently in the calcifying area. Mononuclear macrophages showed not only phagocytosis and digestion of cellular debris and bone spicules in the osteoid, but also active incorporation of calcified bone matrix that had been detached from its surroundings by its pseudopod-like projections from long cytoplasmic processes. Collagen fibrils were seldom observed within the macrophages. These observations suggest that in our culture system osteoblast-like cells and macrophages at bone formation sites have a phagocytic role in bone remodeling.

Animals↗
PubMed1986

An ultrastructural study of phagocytosis in bone by osteoblastic cells from fetal mouse calvaria in vitro.

Twenty per cent of mature osteoblastic cells from parietal bone fragments in the mineralizing bone matrix phagocytized collagen fibrils. Forty per cent of immature osteoblastic cells in the partially mineralizing osteoid phagocytized collagen fibrils and mineralized bone particles. This phenomenon was most marked in cells containing a lake of glycogen. Thus during bone formation in vitro, osteoblasts may phagocytize bone-tissue components as well as synthesizing them.

Animals↗
PubMed1986

Effects of 1,25-dihydroxyvitamin D3 on osteoblastic MC3T3-E1 cells.

1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] was examined for a possible stimulative effect on osteoblastic MC3T3-E1 cells. During the early period of culture, 1,25-(OH)2D3 had a stimulative effect. During the growth phase, however, the steroid had little effect on either the protein or DNA content of the cultures. 1,25-(OH)2D3 increased bone-liver-kidney-type alkaline phosphatase activity in a dose-related manner up to a concentration of 5 pg/ml; the increase was 2.2-fold over the control value. Studies on the effect of actinomycin D or cycloheximide treatment indicated that the vitamin may enhance de novo synthesis of ALP. The steroid also stimulated type I collagen production dose dependently via an increase in collagen synthesis rather than by inhibition of collagen degradation. MC3T3-E1 cells have a specific receptor for 1,25-(OH)2D3 which has a dissociation constant of 4.17 X 10(-11) M and a sedimentation coefficient of 3.67S. The receptor concentration varied with the period of culture, being higher during the growth phase and lower at confluence, but its affinity did not change. The results indicate that 1,25-(OH)2D3 has a direct specific anabolic effect on osteoblastic cells in vitro during the growth phase and that this effect is related to receptor concentration.

Alkaline Phosphatase↗
PubMed1986

[Computerized control system for administration of the radioisotope use].

An on-line computer system for administration of the radioisotope use has been developed. This system consists of a multi-job type host computer and two sets of personal computers with identification card-readers. The personal computers are employed as terminal devices for radioisotope users. By the use of an identification card, entrance and leaving times are recorded automatically. Furthermore, an easy operation of the personal computer permits users to access to the information of their registered radioisotopes, such as nuclides, chemical forms, updated activities, storage locations, and history of usage. A recording sheet on which those data are printed is provided from the personal computer. After the use of radioisotopes, users can record their data on the recording sheets. These records are used as the input data to this system to update the data of the used radioisotopes. Owing to the concise format of the recording sheet and various sorting programs developed in present work, this system enables us to grasp the exact flow of the radioisotopes from purchase to disposal. Out-put data from high-speed kanji printer can provide many important books which are legally requested to be kept for administration of the radioisotope use.

Computers↗
PubMed1986

Anatomical and functional differences in the Adductor mandibulae muscle between Zaco platypus and Carassius gibelio langsdorfi of the Cyprinidae family.

A histological study has been made on the jaw-closing muscle, Adductor mandibulae, of 2 species of Cyprinidae, Zaco platypus and Carassius gibelio langsdorfi, which show completely different feeding behaviour. The former swims up to the food with its mouth open in rapid current, and the latter sucks food from the bottom into its mouth by enlargement of the buccal and opercular cavities in quite mild current. The latter's feeding behaviour was made repeatedly. The A. mandibulae was divided into its anterior and posterior parts in both fish. The anterior part in Z. platypus was divided into 2 portions, and that of C. gibelio langsdorfi into 3 portions. In each portion of the muscle of both fish, SDH activity in the muscle fibers decreased from the medial to the lateral side. Both fish had 3 types of the fibers on the basis of SDH activity, whereas the combinations of each fiber type were more complex in C. gibelio langsdorfi than in Z. platypus. Moreover, the ratio of fibers with higher SDH activities was larger in C. gibelio langsdorfi than in Z. platypus. And, differences in the number of capillaries per fiber in the same fiber type between the 2 fish suggest a complex adaptation of the jaw-closing muscle to the environmental circumstances of the fish.

Animals↗
PubMed1985

The unique action for bone metabolism of 1 alpha,25-(OH)2D3-26,23-lactone.

[23 (S), 25 (R)]-1 alpha,25-Dihydroxyvitamin D3-26,23-lactone [( 23 (S),25 (R)]-1 alpha,25-(OH) 2D3-26,23-lactone) increased dose-dependently alkaline phosphatase activity in osteoblastic cells, clone MC3T3-E1, in medium containing 0.1% bovine serum albumin. The maximal stimulated enzyme activity per mg protein was 1.6-fold over that of control cultures at 250 pg/ml. The metabolite also increased collagen synthesis in a dose-related fashion. On the other hand, [23 (S),25 (R)]-1 alpha,25-(OH)2D3-26,23-lactone decreased slightly but significantly 45Ca mobilization, and blocked the resorptive action of 1 alpha,25-dihydroxyvitamin D3 but not that of parathyroid hormone, in mouse calvaria in organ culture. These results indicate that [23 (S),25 (R)]-1 alpha, 25-(OH)2D3-26,23-lactone stimulates the differentiation of osteoblasts and inhibits bone resorption in vitro.

Alkaline Phosphatase↗
PubMed1985

Induction of osteoblastic cell differentiation by forskolin. Stimulation of cyclic AMP production and alkaline phosphatase activity.

The effects of forskolin on differentiation of osteoblastic cells (clone MC3T3-E1) cultured in alpha-minimum essential medium containing 0.1% bovine serum albumin were investigated by assays of intracellular cyclic AMP level and alkaline phosphatase activity in the cells. Forskolin increased cyclic AMP production in the cells in a dose-related manner, the maximum increase being 250-fold above that of the controls. Alkaline phosphatase activity in the cells was also elevated as early as 24 h and rose to nearly its maximum at 48 h. The elevation was dose-dependent, with a maximum increase at 5 X 10(-6) M forskolin. Forskolin and prostaglandin E2 showed a supraadditive effect on cyclic AMP production in the cells and had an additive effect on alkaline phosphatase activity, whereas forskolin and dibutyryl cyclic AMP had little additive effect on either cyclic AMP production or enzyme activity. These results suggest that cyclic AMP is closely linked to the differentiation of osteoblastic cells in vivo.

Alkaline Phosphatase↗
PubMed1985

Prostaglandin E2 stimulates collagen and non-collagen protein synthesis and prolyl hydroxylase activity in osteoblastic clone MC3T3-E1 cells.

We investigated the stimulative effect of prostaglandin E2 (PGE2) on an osteoblastic cell line, clone MC3T3-E1, in serum-free medium. PGE2 elevated collagen and non-collagen protein syntheses in a dose-related fashion up to 2 micrograms/ml, the maximal increases being 2- and 3-fold, respectively, over that in the control. Its stimulative effect was evident as early as 12 h. PGE2 slightly increased DNA content, but its effect was less than that on collagen and non-collagen protein syntheses. Moreover, PGE stimulated an increase in prolyl hydroxylase activity with a maximal effect at 1-2 micrograms/ml, the activity being 15-fold over that of the control. These results strongly indicate that PGE2 directly enhances total protein synthesis including that of collagen in osteoblasts in vitro, suggesting its direct effect on bone formation in vivo as well.

Animals↗
PubMed1985

Inductive effects of prostaglandins on alkaline phosphatase in osteoblastic cells, clone MC3T3-E1.

The effects of prostaglandins (PGs) on the induction of alkaline phosphatase (ALP) were investigated in osteoblastic clone MC3T3-E1 cells cultured in serum-free medium. Prostaglandin E2 (PGE2) stimulated ALP activity in the cells in a dose-dependent fashion with a maximal effect which was about twice that in the control cells at concentrations of 100-500 ng/ml. Actinomycin D and cycloheximide inhibited the stimulative effect of PGE2 on ALP activity in the cells. PGE2-induced and native ALPs in the cells were of the same type as that in adult mouse calvaria, being heat-labile, L-homoarginine- and levamisole-sensitive, and L-phenylalanine-insensitive. Isobutyl methylxanthine (IBMX), a cAMP phosphodiesterase inhibitor, stimulated the inductive effect of PGE2 on ALP activity at 0.1 mM, at which concentration IBMX alone had little effect on the activity. PGE2 also increased the intracellular cAMP content in a dose-dependent fashion with a maximal effect at 100 ng/ml. PGE1, PGF1 alpha, and PGF2 alpha (primary PGs like PGE2) increased the activity. Our present results suggest that PGs stimulate the differentiation of osteoblasts and are involved in bone formation in vivo, as well as in bone resorption.

1-Methyl-3-isobutylxanthine↗
PubMed1984

Effects of parathyroid hormone on cAMP production and alkaline phosphatase activity in osteoblastic clone MC3T3-E1 cells.

The effect of parathyroid hormone (PTH) was tested on osteoblastic cells (clone MC3T3-E1) cultured in serum-free medium containing 0.3% bovine serum albumin. PTH stimulated an increase in cAMP production in a dose-related fashion up to a concentration of 0.5 unit/ml, the maximum increase being 23-fold above that of controls. Although PTH did not affect DNA content, this peptide also increased dose-dependently alkaline phosphatase activity up to a concentration of 0.5 unit/ml. PTH plus isobutylmethyl xanthine elevated enzyme activity 1.5-fold over that in PTH-treated cells. These results strongly indicate that PTH has a direct stimulatory effect on the differentiation of osteoblasts via intracellular cAMP production in vitro.

Alkaline Phosphatase↗
PubMed1984

Effect of 1,25-dihydroxyvitamin D3 on alkaline phosphatase activity and collagen synthesis in osteoblastic cells, clone MC3T3-E1.

A stimulative effect of 1,25-dihydroxyvitamin D3 was tested on osteoblastic cells, clone MC3T3-E1, cultured in serum-free medium with 0.1% bovine serum albumin. This steroid increased alkaline phosphatase activity in a dose-related fashion. The steroid also stimulated dose-dependently collagen and non-collagen protein syntheses, their maximal effects being observed at 12 and 24 h, respectively. The incorporation of [3H]-proline into collagen or non-collagen protein in cells exposed to this steroid for 12 h was 2.9 or 1.9-fold over that of control cultures, respectively. These results strongly indicate the stimulative effects of 1,25-dihydroxyvitamin D3 on the differentiation of osteoblasts in vitro.

Alkaline Phosphatase↗
PubMed1984

Effect of transferrin on alkaline phosphatase activity and collagen synthesis in osteoblastic cells derived from newborn mouse calvaria.

The effect of transferrin was tested on osteoblastic cells (clone MC3T3-E1) cultured in serum-free medium containing 1% bovine serum albumin (BSA). Transferrin (Tf) stimulated increases of protein content and protein synthesis, but not of DNA content and cell number, in the cells. This protein also increased alkaline phosphatase activity and collagen synthesis in combination with 1% BSA. Actinomycin D and cycloheximide inhibited alkaline phosphatase activity induced by Tf, suggesting that Tf may enhance de novo synthesis of the enzyme. These results indicate that Tf may be involved in differentiation of osteoblastic cells, but not in their proliferation, in vitro.

Alkaline Phosphatase↗
PubMed1984

[Trapping of volatile iodine by an activated carbon fiber filter].

Model experiments for a simple and effective trapping device of volatile iodine that is generated during radioiodination of biomacromolecules were performed using an activated carbon fiber filter. Over 99.9% of the radioactivity was trapped by the first sheet, when a stream of the volatile radioactive iodine was passed through the layer consisting of several sheets of carbon fiber filter of pore-size 2nm preceded by two or three sheets of urethane foam filter to eliminate the water vapor. Since the carbon fiber filter has very little resistance to the gas flow, the device seems applicable to the small filter chamber for the radioiodination hood.

Charcoal↗
PubMed1984

Propylthiouracil-induced diffuse interstitial pneumonitis.

Cough productive of sputum, exertional dyspnea, and hypoxemia developed in two patients with Graves' disease after six months (patient 1) or three weeks (patient 2) of treatment with propylthiouracil, 300 mg/day. Chest roentgenograms and transbronchial lung biopsy specimens revealed diffuse interstitial pneumonitis. Lymphocyte transformation by phytohemagglutinin was highly stimulated by propylthiouracil. Symptoms and signs improved after cessation of the drug therapy and administration of prednisolone acetate. These cases represent the first report of a complication of diffuse interstitial pneumonitis induced by propylthiouracil.

Aged↗
PubMed1983

1 alpha, 25-Dihydroxyvitamin D3 and analogues of vitamin D3 induce alkaline phosphatase activity in osteoblastic cells derived from newborn mouse calvaria.

In order to study the effects of vitamin D metabolites on bone metabolism, clone MC3T3-E1 cells, which have retained osteoblastic activity, were cultured with various concentrations of the hormone, 1 alpha, 25-dihydroxyvitamin D3 [1 alpha, 25 (OH)2D3]. A physiological concentration of 1 alpha, 25 (OH)2D3 stimulated alkaline phosphatase (ALP) activity in the cells. Other metabolites--1 alpha, 24-dihydroxyvitamin D3 [1 alpha, 24 (OH)2D3], 1 alpha-hydroxyvitamin D3 [1 alpha (OH)D3], and 24R,25-dihydroxyvitamin D3 [24R,25 (OH)2D3]--also induced increases in ALP activity in a dose-dependent fashion. However, their effective concentrations were 100 or 1,000 times greater than that of 1 alpha, 25 (OH)2D3. Hormone-induced and native ALP activities in the cells were of the same type as that found in newborn mouse calvaria; that is, they were heat-labile, L-homoarginine- and levamisole-sensitive, and L-phenylalanine-insensitive (liver-bone-kidney type). These results show that vitamin D metabolites stimulate bone formation in vitro and that they may be involved in bone formation in vivo as well.

Alkaline Phosphatase↗